/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Bitstream/BitstreamReader.h

Bug Summary

File:	include/llvm/Bitstream/BitstreamReader.h
Warning:	line 220, column 39 The result of the right shift is undefined due to shifting by '64', which is greater or equal to the width of type 'llvm::SimpleBitstreamCursor::word_t'

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name BitcodeAnalyzer.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=none -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-10~svn374877/build-llvm/lib/Bitcode/Reader -I /build/llvm-toolchain-snapshot-10~svn374877/lib/Bitcode/Reader -I /build/llvm-toolchain-snapshot-10~svn374877/build-llvm/include -I /build/llvm-toolchain-snapshot-10~svn374877/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-10~svn374877/build-llvm/lib/Bitcode/Reader -fdebug-prefix-map=/build/llvm-toolchain-snapshot-10~svn374877=. -ferror-limit 19 -fmessage-length 0 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2019-10-15-233810-7101-1 -x c++ /build/llvm-toolchain-snapshot-10~svn374877/lib/Bitcode/Reader/BitcodeAnalyzer.cpp

/build/llvm-toolchain-snapshot-10~svn374877/lib/Bitcode/Reader/BitcodeAnalyzer.cpp

→

1//===- BitcodeAnalyzer.cpp - Internal BitcodeAnalyzer implementation ------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//

9#include "llvm/Bitcode/BitcodeAnalyzer.h"
10#include "llvm/Bitcode/BitcodeReader.h"
11#include "llvm/Bitcode/LLVMBitCodes.h"
12#include "llvm/Bitstream/BitCodes.h"
13#include "llvm/Bitstream/BitstreamReader.h"
14#include "llvm/Support/Format.h"
15#include "llvm/Support/SHA1.h"

17using namespace llvm;

19static Error reportError(StringRef Message) {
return createStringError(std::errc::illegal_byte_sequence, Message.data());
21}

23/// Return a symbolic block name if known, otherwise return null.
24static Optional<const char *> GetBlockName(unsigned BlockID,
                                         const BitstreamBlockInfo &BlockInfo,
                                         CurStreamTypeType CurStreamType) {
// Standard blocks for all bitcode files.
if (BlockID < bitc::FIRST_APPLICATION_BLOCKID) {
  if (BlockID == bitc::BLOCKINFO_BLOCK_ID)
    return "BLOCKINFO_BLOCK";
  return None;
}

// Check to see if we have a blockinfo record for this block, with a name.
if (const BitstreamBlockInfo::BlockInfo *Info =
        BlockInfo.getBlockInfo(BlockID)) {
  if (!Info->Name.empty())
    return Info->Name.c_str();
}

if (CurStreamType != LLVMIRBitstream)
  return None;

switch (BlockID) {
default:
  return None;
case bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID:
  return "OPERAND_BUNDLE_TAGS_BLOCK";
case bitc::MODULE_BLOCK_ID:
  return "MODULE_BLOCK";
case bitc::PARAMATTR_BLOCK_ID:
  return "PARAMATTR_BLOCK";
case bitc::PARAMATTR_GROUP_BLOCK_ID:
  return "PARAMATTR_GROUP_BLOCK_ID";
case bitc::TYPE_BLOCK_ID_NEW:
  return "TYPE_BLOCK_ID";
case bitc::CONSTANTS_BLOCK_ID:
  return "CONSTANTS_BLOCK";
case bitc::FUNCTION_BLOCK_ID:
  return "FUNCTION_BLOCK";
case bitc::IDENTIFICATION_BLOCK_ID:
  return "IDENTIFICATION_BLOCK_ID";
case bitc::VALUE_SYMTAB_BLOCK_ID:
  return "VALUE_SYMTAB";
case bitc::METADATA_BLOCK_ID:
  return "METADATA_BLOCK";
case bitc::METADATA_KIND_BLOCK_ID:
  return "METADATA_KIND_BLOCK";
case bitc::METADATA_ATTACHMENT_ID:
  return "METADATA_ATTACHMENT_BLOCK";
case bitc::USELIST_BLOCK_ID:
  return "USELIST_BLOCK_ID";
case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
  return "GLOBALVAL_SUMMARY_BLOCK";
case bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID:
  return "FULL_LTO_GLOBALVAL_SUMMARY_BLOCK";
case bitc::MODULE_STRTAB_BLOCK_ID:
  return "MODULE_STRTAB_BLOCK";
case bitc::STRTAB_BLOCK_ID:
  return "STRTAB_BLOCK";
case bitc::SYMTAB_BLOCK_ID:
  return "SYMTAB_BLOCK";
}
84}

86/// Return a symbolic code name if known, otherwise return null.
87static Optional<const char *> GetCodeName(unsigned CodeID, unsigned BlockID,
                                        const BitstreamBlockInfo &BlockInfo,
                                        CurStreamTypeType CurStreamType) {
// Standard blocks for all bitcode files.
if (BlockID < bitc::FIRST_APPLICATION_BLOCKID) {
  if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
    switch (CodeID) {
    default:
      return None;
    case bitc::BLOCKINFO_CODE_SETBID:
      return "SETBID";
    case bitc::BLOCKINFO_CODE_BLOCKNAME:
      return "BLOCKNAME";
    case bitc::BLOCKINFO_CODE_SETRECORDNAME:
      return "SETRECORDNAME";
    }
  }
  return None;
}

// Check to see if we have a blockinfo record for this record, with a name.
if (const BitstreamBlockInfo::BlockInfo *Info =
        BlockInfo.getBlockInfo(BlockID)) {
  for (unsigned i = 0, e = Info->RecordNames.size(); i != e; ++i)
    if (Info->RecordNames[i].first == CodeID)
      return Info->RecordNames[i].second.c_str();
}

if (CurStreamType != LLVMIRBitstream)
  return None;

118#define STRINGIFY_CODE(PREFIX, CODE)                                           \
case bitc::PREFIX##_##CODE:                                                  \
  return #CODE;
switch (BlockID) {
default:
  return None;
case bitc::MODULE_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(MODULE_CODE, VERSION)
    STRINGIFY_CODE(MODULE_CODE, TRIPLE)
    STRINGIFY_CODE(MODULE_CODE, DATALAYOUT)
    STRINGIFY_CODE(MODULE_CODE, ASM)
    STRINGIFY_CODE(MODULE_CODE, SECTIONNAME)
    STRINGIFY_CODE(MODULE_CODE, DEPLIB) // FIXME: Remove in 4.0
    STRINGIFY_CODE(MODULE_CODE, GLOBALVAR)
    STRINGIFY_CODE(MODULE_CODE, FUNCTION)
    STRINGIFY_CODE(MODULE_CODE, ALIAS)
    STRINGIFY_CODE(MODULE_CODE, GCNAME)
    STRINGIFY_CODE(MODULE_CODE, VSTOFFSET)
    STRINGIFY_CODE(MODULE_CODE, METADATA_VALUES_UNUSED)
    STRINGIFY_CODE(MODULE_CODE, SOURCE_FILENAME)
    STRINGIFY_CODE(MODULE_CODE, HASH)
  }
case bitc::IDENTIFICATION_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(IDENTIFICATION_CODE, STRING)
    STRINGIFY_CODE(IDENTIFICATION_CODE, EPOCH)
  }
case bitc::PARAMATTR_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
  // FIXME: Should these be different?
  case bitc::PARAMATTR_CODE_ENTRY_OLD:
    return "ENTRY";
  case bitc::PARAMATTR_CODE_ENTRY:
    return "ENTRY";
  }
case bitc::PARAMATTR_GROUP_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
  case bitc::PARAMATTR_GRP_CODE_ENTRY:
    return "ENTRY";
  }
case bitc::TYPE_BLOCK_ID_NEW:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(TYPE_CODE, NUMENTRY)
    STRINGIFY_CODE(TYPE_CODE, VOID)
    STRINGIFY_CODE(TYPE_CODE, FLOAT)
    STRINGIFY_CODE(TYPE_CODE, DOUBLE)
    STRINGIFY_CODE(TYPE_CODE, LABEL)
    STRINGIFY_CODE(TYPE_CODE, OPAQUE)
    STRINGIFY_CODE(TYPE_CODE, INTEGER)
    STRINGIFY_CODE(TYPE_CODE, POINTER)
    STRINGIFY_CODE(TYPE_CODE, ARRAY)
    STRINGIFY_CODE(TYPE_CODE, VECTOR)
    STRINGIFY_CODE(TYPE_CODE, X86_FP80)
    STRINGIFY_CODE(TYPE_CODE, FP128)
    STRINGIFY_CODE(TYPE_CODE, PPC_FP128)
    STRINGIFY_CODE(TYPE_CODE, METADATA)
    STRINGIFY_CODE(TYPE_CODE, STRUCT_ANON)
    STRINGIFY_CODE(TYPE_CODE, STRUCT_NAME)
    STRINGIFY_CODE(TYPE_CODE, STRUCT_NAMED)
    STRINGIFY_CODE(TYPE_CODE, FUNCTION)
  }

case bitc::CONSTANTS_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(CST_CODE, SETTYPE)
    STRINGIFY_CODE(CST_CODE, NULL__null)
    STRINGIFY_CODE(CST_CODE, UNDEF)
    STRINGIFY_CODE(CST_CODE, INTEGER)
    STRINGIFY_CODE(CST_CODE, WIDE_INTEGER)
    STRINGIFY_CODE(CST_CODE, FLOAT)
    STRINGIFY_CODE(CST_CODE, AGGREGATE)
    STRINGIFY_CODE(CST_CODE, STRING)
    STRINGIFY_CODE(CST_CODE, CSTRING)
    STRINGIFY_CODE(CST_CODE, CE_BINOP)
    STRINGIFY_CODE(CST_CODE, CE_CAST)
    STRINGIFY_CODE(CST_CODE, CE_GEP)
    STRINGIFY_CODE(CST_CODE, CE_INBOUNDS_GEP)
    STRINGIFY_CODE(CST_CODE, CE_SELECT)
    STRINGIFY_CODE(CST_CODE, CE_EXTRACTELT)
    STRINGIFY_CODE(CST_CODE, CE_INSERTELT)
    STRINGIFY_CODE(CST_CODE, CE_SHUFFLEVEC)
    STRINGIFY_CODE(CST_CODE, CE_CMP)
    STRINGIFY_CODE(CST_CODE, INLINEASM)
    STRINGIFY_CODE(CST_CODE, CE_SHUFVEC_EX)
    STRINGIFY_CODE(CST_CODE, CE_UNOP)
  case bitc::CST_CODE_BLOCKADDRESS:
    return "CST_CODE_BLOCKADDRESS";
    STRINGIFY_CODE(CST_CODE, DATA)
  }
case bitc::FUNCTION_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(FUNC_CODE, DECLAREBLOCKS)
    STRINGIFY_CODE(FUNC_CODE, INST_BINOP)
    STRINGIFY_CODE(FUNC_CODE, INST_CAST)
    STRINGIFY_CODE(FUNC_CODE, INST_GEP_OLD)
    STRINGIFY_CODE(FUNC_CODE, INST_INBOUNDS_GEP_OLD)
    STRINGIFY_CODE(FUNC_CODE, INST_SELECT)
    STRINGIFY_CODE(FUNC_CODE, INST_EXTRACTELT)
    STRINGIFY_CODE(FUNC_CODE, INST_INSERTELT)
    STRINGIFY_CODE(FUNC_CODE, INST_SHUFFLEVEC)
    STRINGIFY_CODE(FUNC_CODE, INST_CMP)
    STRINGIFY_CODE(FUNC_CODE, INST_RET)
    STRINGIFY_CODE(FUNC_CODE, INST_BR)
    STRINGIFY_CODE(FUNC_CODE, INST_SWITCH)
    STRINGIFY_CODE(FUNC_CODE, INST_INVOKE)
    STRINGIFY_CODE(FUNC_CODE, INST_UNOP)
    STRINGIFY_CODE(FUNC_CODE, INST_UNREACHABLE)
    STRINGIFY_CODE(FUNC_CODE, INST_CLEANUPRET)
    STRINGIFY_CODE(FUNC_CODE, INST_CATCHRET)
    STRINGIFY_CODE(FUNC_CODE, INST_CATCHPAD)
    STRINGIFY_CODE(FUNC_CODE, INST_PHI)
    STRINGIFY_CODE(FUNC_CODE, INST_ALLOCA)
    STRINGIFY_CODE(FUNC_CODE, INST_LOAD)
    STRINGIFY_CODE(FUNC_CODE, INST_VAARG)
    STRINGIFY_CODE(FUNC_CODE, INST_STORE)
    STRINGIFY_CODE(FUNC_CODE, INST_EXTRACTVAL)
    STRINGIFY_CODE(FUNC_CODE, INST_INSERTVAL)
    STRINGIFY_CODE(FUNC_CODE, INST_CMP2)
    STRINGIFY_CODE(FUNC_CODE, INST_VSELECT)
    STRINGIFY_CODE(FUNC_CODE, DEBUG_LOC_AGAIN)
    STRINGIFY_CODE(FUNC_CODE, INST_CALL)
    STRINGIFY_CODE(FUNC_CODE, DEBUG_LOC)
    STRINGIFY_CODE(FUNC_CODE, INST_GEP)
    STRINGIFY_CODE(FUNC_CODE, OPERAND_BUNDLE)
    STRINGIFY_CODE(FUNC_CODE, INST_FENCE)
    STRINGIFY_CODE(FUNC_CODE, INST_ATOMICRMW)
    STRINGIFY_CODE(FUNC_CODE, INST_LOADATOMIC)
    STRINGIFY_CODE(FUNC_CODE, INST_STOREATOMIC)
    STRINGIFY_CODE(FUNC_CODE, INST_CMPXCHG)
    STRINGIFY_CODE(FUNC_CODE, INST_CALLBR)
  }
case bitc::VALUE_SYMTAB_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(VST_CODE, ENTRY)
    STRINGIFY_CODE(VST_CODE, BBENTRY)
    STRINGIFY_CODE(VST_CODE, FNENTRY)
    STRINGIFY_CODE(VST_CODE, COMBINED_ENTRY)
  }
case bitc::MODULE_STRTAB_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(MST_CODE, ENTRY)
    STRINGIFY_CODE(MST_CODE, HASH)
  }
case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
case bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(FS, PERMODULE)
    STRINGIFY_CODE(FS, PERMODULE_PROFILE)
    STRINGIFY_CODE(FS, PERMODULE_RELBF)
    STRINGIFY_CODE(FS, PERMODULE_GLOBALVAR_INIT_REFS)
    STRINGIFY_CODE(FS, PERMODULE_VTABLE_GLOBALVAR_INIT_REFS)
    STRINGIFY_CODE(FS, COMBINED)
    STRINGIFY_CODE(FS, COMBINED_PROFILE)
    STRINGIFY_CODE(FS, COMBINED_GLOBALVAR_INIT_REFS)
    STRINGIFY_CODE(FS, ALIAS)
    STRINGIFY_CODE(FS, COMBINED_ALIAS)
    STRINGIFY_CODE(FS, COMBINED_ORIGINAL_NAME)
    STRINGIFY_CODE(FS, VERSION)
    STRINGIFY_CODE(FS, FLAGS)
    STRINGIFY_CODE(FS, TYPE_TESTS)
    STRINGIFY_CODE(FS, TYPE_TEST_ASSUME_VCALLS)
    STRINGIFY_CODE(FS, TYPE_CHECKED_LOAD_VCALLS)
    STRINGIFY_CODE(FS, TYPE_TEST_ASSUME_CONST_VCALL)
    STRINGIFY_CODE(FS, TYPE_CHECKED_LOAD_CONST_VCALL)
    STRINGIFY_CODE(FS, VALUE_GUID)
    STRINGIFY_CODE(FS, CFI_FUNCTION_DEFS)
    STRINGIFY_CODE(FS, CFI_FUNCTION_DECLS)
    STRINGIFY_CODE(FS, TYPE_ID)
    STRINGIFY_CODE(FS, TYPE_ID_METADATA)
  }
case bitc::METADATA_ATTACHMENT_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(METADATA, ATTACHMENT)
  }
case bitc::METADATA_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(METADATA, STRING_OLD)
    STRINGIFY_CODE(METADATA, VALUE)
    STRINGIFY_CODE(METADATA, NODE)
    STRINGIFY_CODE(METADATA, NAME)
    STRINGIFY_CODE(METADATA, DISTINCT_NODE)
    STRINGIFY_CODE(METADATA, KIND) // Older bitcode has it in a MODULE_BLOCK
    STRINGIFY_CODE(METADATA, LOCATION)
    STRINGIFY_CODE(METADATA, OLD_NODE)
    STRINGIFY_CODE(METADATA, OLD_FN_NODE)
    STRINGIFY_CODE(METADATA, NAMED_NODE)
    STRINGIFY_CODE(METADATA, GENERIC_DEBUG)
    STRINGIFY_CODE(METADATA, SUBRANGE)
    STRINGIFY_CODE(METADATA, ENUMERATOR)
    STRINGIFY_CODE(METADATA, BASIC_TYPE)
    STRINGIFY_CODE(METADATA, FILE)
    STRINGIFY_CODE(METADATA, DERIVED_TYPE)
    STRINGIFY_CODE(METADATA, COMPOSITE_TYPE)
    STRINGIFY_CODE(METADATA, SUBROUTINE_TYPE)
    STRINGIFY_CODE(METADATA, COMPILE_UNIT)
    STRINGIFY_CODE(METADATA, SUBPROGRAM)
    STRINGIFY_CODE(METADATA, LEXICAL_BLOCK)
    STRINGIFY_CODE(METADATA, LEXICAL_BLOCK_FILE)
    STRINGIFY_CODE(METADATA, NAMESPACE)
    STRINGIFY_CODE(METADATA, TEMPLATE_TYPE)
    STRINGIFY_CODE(METADATA, TEMPLATE_VALUE)
    STRINGIFY_CODE(METADATA, GLOBAL_VAR)
    STRINGIFY_CODE(METADATA, LOCAL_VAR)
    STRINGIFY_CODE(METADATA, EXPRESSION)
    STRINGIFY_CODE(METADATA, OBJC_PROPERTY)
    STRINGIFY_CODE(METADATA, IMPORTED_ENTITY)
    STRINGIFY_CODE(METADATA, MODULE)
    STRINGIFY_CODE(METADATA, MACRO)
    STRINGIFY_CODE(METADATA, MACRO_FILE)
    STRINGIFY_CODE(METADATA, STRINGS)
    STRINGIFY_CODE(METADATA, GLOBAL_DECL_ATTACHMENT)
    STRINGIFY_CODE(METADATA, GLOBAL_VAR_EXPR)
    STRINGIFY_CODE(METADATA, INDEX_OFFSET)
    STRINGIFY_CODE(METADATA, INDEX)
  }
case bitc::METADATA_KIND_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
    STRINGIFY_CODE(METADATA, KIND)
  }
case bitc::USELIST_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
  case bitc::USELIST_CODE_DEFAULT:
    return "USELIST_CODE_DEFAULT";
  case bitc::USELIST_CODE_BB:
    return "USELIST_CODE_BB";
  }

case bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
  case bitc::OPERAND_BUNDLE_TAG:
    return "OPERAND_BUNDLE_TAG";
  }
case bitc::STRTAB_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
  case bitc::STRTAB_BLOB:
    return "BLOB";
  }
case bitc::SYMTAB_BLOCK_ID:
  switch (CodeID) {
  default:
    return None;
  case bitc::SYMTAB_BLOB:
    return "BLOB";
  }
}
396#undef STRINGIFY_CODE
397}

399static void printSize(raw_ostream &OS, double Bits) {
OS << format("%.2f/%.2fB/%luW", Bits, Bits / 8, (unsigned long)(Bits / 32));
401}
402static void printSize(raw_ostream &OS, uint64_t Bits) {
OS << format("%lub/%.2fB/%luW", (unsigned long)Bits, (double)Bits / 8,
             (unsigned long)(Bits / 32));
405}

407static Expected<CurStreamTypeType> ReadSignature(BitstreamCursor &Stream) {
auto tryRead = [&Stream](char &Dest, size_t size) -> Error {
  if (Expected<SimpleBitstreamCursor::word_t> MaybeWord = Stream.Read(size))
    Dest = MaybeWord.get();
  else
    return MaybeWord.takeError();
  return Error::success();
};

char Signature[6];
if (Error Err = tryRead(Signature[0], 8))
  return std::move(Err);
if (Error Err = tryRead(Signature[1], 8))
  return std::move(Err);

// Autodetect the file contents, if it is one we know.
if (Signature[0] == 'C' && Signature[1] == 'P') {
  if (Error Err = tryRead(Signature[2], 8))
    return std::move(Err);
  if (Error Err = tryRead(Signature[3], 8))
    return std::move(Err);
  if (Signature[2] == 'C' && Signature[3] == 'H')
    return ClangSerializedASTBitstream;
} else if (Signature[0] == 'D' && Signature[1] == 'I') {
  if (Error Err = tryRead(Signature[2], 8))
    return std::move(Err);
  if (Error Err = tryRead(Signature[3], 8))
    return std::move(Err);
  if (Signature[2] == 'A' && Signature[3] == 'G')
    return ClangSerializedDiagnosticsBitstream;
} else if (Signature[0] == 'R' && Signature[1] == 'M') {
  if (Error Err = tryRead(Signature[2], 8))
    return std::move(Err);
  if (Error Err = tryRead(Signature[3], 8))
    return std::move(Err);
  if (Signature[2] == 'R' && Signature[3] == 'K')
    return LLVMBitstreamRemarks;
} else {
  if (Error Err = tryRead(Signature[2], 4))
    return std::move(Err);
  if (Error Err = tryRead(Signature[3], 4))
    return std::move(Err);
  if (Error Err = tryRead(Signature[4], 4))
    return std::move(Err);
  if (Error Err = tryRead(Signature[5], 4))
    return std::move(Err);
  if (Signature[0] == 'B' && Signature[1] == 'C' && Signature[2] == 0x0 &&
      Signature[3] == 0xC && Signature[4] == 0xE && Signature[5] == 0xD)
    return LLVMIRBitstream;
}
return UnknownBitstream;
458}

460static Expected<CurStreamTypeType> analyzeHeader(Optional<BCDumpOptions> O,
                                               BitstreamCursor &Stream) {
ArrayRef<uint8_t> Bytes = Stream.getBitcodeBytes();
const unsigned char *BufPtr = (const unsigned char *)Bytes.data();
const unsigned char *EndBufPtr = BufPtr + Bytes.size();

// If we have a wrapper header, parse it and ignore the non-bc file
// contents. The magic number is 0x0B17C0DE stored in little endian.
if (isBitcodeWrapper(BufPtr, EndBufPtr)) {
  if (Bytes.size() < BWH_HeaderSize)
    return reportError("Invalid bitcode wrapper header");

  if (O) {
    unsigned Magic = support::endian::read32le(&BufPtr[BWH_MagicField]);
    unsigned Version = support::endian::read32le(&BufPtr[BWH_VersionField]);
    unsigned Offset = support::endian::read32le(&BufPtr[BWH_OffsetField]);
    unsigned Size = support::endian::read32le(&BufPtr[BWH_SizeField]);
    unsigned CPUType = support::endian::read32le(&BufPtr[BWH_CPUTypeField]);

    O->OS << "<BITCODE_WRAPPER_HEADER"
          << " Magic=" << format_hex(Magic, 10)
          << " Version=" << format_hex(Version, 10)
          << " Offset=" << format_hex(Offset, 10)
          << " Size=" << format_hex(Size, 10)
          << " CPUType=" << format_hex(CPUType, 10) << "/>\n";
  }

  if (SkipBitcodeWrapperHeader(BufPtr, EndBufPtr, true))
    return reportError("Invalid bitcode wrapper header");
}

// Use the cursor modified by skipping the wrapper header.
Stream = BitstreamCursor(ArrayRef<uint8_t>(BufPtr, EndBufPtr));

return ReadSignature(Stream);
495}

497static bool canDecodeBlob(unsigned Code, unsigned BlockID) {
return BlockID == bitc::METADATA_BLOCK_ID && Code == bitc::METADATA_STRINGS;
499}

501Error BitcodeAnalyzer::decodeMetadataStringsBlob(StringRef Indent,
                                               ArrayRef<uint64_t> Record,
                                               StringRef Blob,
                                               raw_ostream &OS) {
if (Blob.empty())
  return reportError("Cannot decode empty blob.");

if (Record.size() != 2)
  return reportError(
      "Decoding metadata strings blob needs two record entries.");

unsigned NumStrings = Record[0];
unsigned StringsOffset = Record[1];
OS << " num-strings = " << NumStrings << " {\n";

StringRef Lengths = Blob.slice(0, StringsOffset);
SimpleBitstreamCursor R(Lengths);
StringRef Strings = Blob.drop_front(StringsOffset);
do {
  if (R.AtEndOfStream())
    return reportError("bad length");

  Expected<uint32_t> MaybeSize = R.ReadVBR(6);
  if (!MaybeSize)
    return MaybeSize.takeError();
  uint32_t Size = MaybeSize.get();
  if (Strings.size() < Size)
    return reportError("truncated chars");

  OS << Indent << "    '";
  OS.write_escaped(Strings.slice(0, Size), /*hex=*/true);
  OS << "'\n";
  Strings = Strings.drop_front(Size);
} while (--NumStrings);

OS << Indent << "  }";
return Error::success();
538}

540BitcodeAnalyzer::BitcodeAnalyzer(StringRef Buffer,
                               Optional<StringRef> BlockInfoBuffer)
  : Stream(Buffer) {
if (BlockInfoBuffer)
  BlockInfoStream.emplace(*BlockInfoBuffer);
545}

547Error BitcodeAnalyzer::analyze(Optional<BCDumpOptions> O,
                             Optional<StringRef> CheckHash) {
Expected<CurStreamTypeType> MaybeType = analyzeHeader(O, Stream);
if (!MaybeType)
  return MaybeType.takeError();
else
  CurStreamType = *MaybeType;

Stream.setBlockInfo(&BlockInfo);

// Read block info from BlockInfoStream, if specified.
// The block info must be a top-level block.
if (BlockInfoStream) {
  BitstreamCursor BlockInfoCursor(*BlockInfoStream);
  Expected<CurStreamTypeType> H = analyzeHeader(O, BlockInfoCursor);
  if (!H)
    return H.takeError();

  while (!BlockInfoCursor.AtEndOfStream()) {
    Expected<unsigned> MaybeCode = BlockInfoCursor.ReadCode();
    if (!MaybeCode)
      return MaybeCode.takeError();
    if (MaybeCode.get() != bitc::ENTER_SUBBLOCK)
      return reportError("Invalid record at top-level in block info file");

    Expected<unsigned> MaybeBlockID = BlockInfoCursor.ReadSubBlockID();
    if (!MaybeBlockID)
      return MaybeBlockID.takeError();
    if (MaybeBlockID.get() == bitc::BLOCKINFO_BLOCK_ID) {
      Expected<Optional<BitstreamBlockInfo>> MaybeNewBlockInfo =
          BlockInfoCursor.ReadBlockInfoBlock(/*ReadBlockInfoNames=*/true);
      if (!MaybeNewBlockInfo)
        return MaybeNewBlockInfo.takeError();
      Optional<BitstreamBlockInfo> NewBlockInfo =
          std::move(MaybeNewBlockInfo.get());
      if (!NewBlockInfo)
        return reportError("Malformed BlockInfoBlock in block info file");
      BlockInfo = std::move(*NewBlockInfo);
      break;
    }

    if (Error Err = BlockInfoCursor.SkipBlock())
      return Err;
  }
}

// Parse the top-level structure.  We only allow blocks at the top-level.
while (!Stream.AtEndOfStream()) {
  Expected<unsigned> MaybeCode = Stream.ReadCode();
  if (!MaybeCode)
    return MaybeCode.takeError();
  if (MaybeCode.get() != bitc::ENTER_SUBBLOCK)
    return reportError("Invalid record at top-level");

  Expected<unsigned> MaybeBlockID = Stream.ReadSubBlockID();
  if (!MaybeBlockID)
    return MaybeBlockID.takeError();

  if (Error E = parseBlock(MaybeBlockID.get(), 0, O, CheckHash))
    return E;
  ++NumTopBlocks;
}

return Error::success();
611}

613void BitcodeAnalyzer::printStats(BCDumpOptions O,
                               Optional<StringRef> Filename) {
uint64_t BufferSizeBits = Stream.getBitcodeBytes().size() * CHAR_BIT8;
// Print a summary of the read file.
O.OS << "Summary ";
if (Filename)
  O.OS << "of " << Filename->data() << ":\n";
O.OS << "         Total size: ";
printSize(O.OS, BufferSizeBits);
O.OS << "\n";
O.OS << "        Stream type: ";
switch (CurStreamType) {
case UnknownBitstream:
  O.OS << "unknown\n";
  break;
case LLVMIRBitstream:
  O.OS << "LLVM IR\n";
  break;
case ClangSerializedASTBitstream:
  O.OS << "Clang Serialized AST\n";
  break;
case ClangSerializedDiagnosticsBitstream:
  O.OS << "Clang Serialized Diagnostics\n";
  break;
case LLVMBitstreamRemarks:
  O.OS << "LLVM Remarks\n";
  break;
}
O.OS << "  # Toplevel Blocks: " << NumTopBlocks << "\n";
O.OS << "\n";

// Emit per-block stats.
O.OS << "Per-block Summary:\n";
for (std::map<unsigned, PerBlockIDStats>::iterator I = BlockIDStats.begin(),
                                                   E = BlockIDStats.end();
     I != E; ++I) {
  O.OS << "  Block ID #" << I->first;
  if (Optional<const char *> BlockName =
          GetBlockName(I->first, BlockInfo, CurStreamType))
    O.OS << " (" << *BlockName << ")";
  O.OS << ":\n";

  const PerBlockIDStats &Stats = I->second;
  O.OS << "      Num Instances: " << Stats.NumInstances << "\n";
  O.OS << "         Total Size: ";
  printSize(O.OS, Stats.NumBits);
  O.OS << "\n";
  double pct = (Stats.NumBits * 100.0) / BufferSizeBits;
  O.OS << "    Percent of file: " << format("%2.4f%%", pct) << "\n";
  if (Stats.NumInstances > 1) {
    O.OS << "       Average Size: ";
    printSize(O.OS, Stats.NumBits / (double)Stats.NumInstances);
    O.OS << "\n";
    O.OS << "  Tot/Avg SubBlocks: " << Stats.NumSubBlocks << "/"
         << Stats.NumSubBlocks / (double)Stats.NumInstances << "\n";
    O.OS << "    Tot/Avg Abbrevs: " << Stats.NumAbbrevs << "/"
         << Stats.NumAbbrevs / (double)Stats.NumInstances << "\n";
    O.OS << "    Tot/Avg Records: " << Stats.NumRecords << "/"
         << Stats.NumRecords / (double)Stats.NumInstances << "\n";
  } else {
    O.OS << "      Num SubBlocks: " << Stats.NumSubBlocks << "\n";
    O.OS << "        Num Abbrevs: " << Stats.NumAbbrevs << "\n";
    O.OS << "        Num Records: " << Stats.NumRecords << "\n";
  }
  if (Stats.NumRecords) {
    double pct = (Stats.NumAbbreviatedRecords * 100.0) / Stats.NumRecords;
    O.OS << "    Percent Abbrevs: " << format("%2.4f%%", pct) << "\n";
  }
  O.OS << "\n";

  // Print a histogram of the codes we see.
  if (O.Histogram && !Stats.CodeFreq.empty()) {
    std::vector<std::pair<unsigned, unsigned>> FreqPairs; // <freq,code>
    for (unsigned i = 0, e = Stats.CodeFreq.size(); i != e; ++i)
      if (unsigned Freq = Stats.CodeFreq[i].NumInstances)
        FreqPairs.push_back(std::make_pair(Freq, i));
    llvm::stable_sort(FreqPairs);
    std::reverse(FreqPairs.begin(), FreqPairs.end());

    O.OS << "\tRecord Histogram:\n";
    O.OS << "\t\t  Count    # Bits     b/Rec   % Abv  Record Kind\n";
    for (unsigned i = 0, e = FreqPairs.size(); i != e; ++i) {
      const PerRecordStats &RecStats = Stats.CodeFreq[FreqPairs[i].second];

      O.OS << format("\t\t%7d %9lu", RecStats.NumInstances,
                     (unsigned long)RecStats.TotalBits);

      if (RecStats.NumInstances > 1)
        O.OS << format(" %9.1f",
                       (double)RecStats.TotalBits / RecStats.NumInstances);
      else
        O.OS << "          ";

      if (RecStats.NumAbbrev)
        O.OS << format(" %7.2f", (double)RecStats.NumAbbrev /
                                     RecStats.NumInstances * 100);
      else
        O.OS << "        ";

      O.OS << "  ";
      if (Optional<const char *> CodeName = GetCodeName(
              FreqPairs[i].second, I->first, BlockInfo, CurStreamType))
        O.OS << *CodeName << "\n";
      else
        O.OS << "UnknownCode" << FreqPairs[i].second << "\n";
    }
    O.OS << "\n";
  }
}
722}

724Error BitcodeAnalyzer::parseBlock(unsigned BlockID, unsigned IndentLevel,
                                Optional<BCDumpOptions> O,
                                Optional<StringRef> CheckHash) {
std::string Indent(IndentLevel * 2, ' ');
uint64_t BlockBitStart = Stream.GetCurrentBitNo();

// Get the statistics for this BlockID.
PerBlockIDStats &BlockStats = BlockIDStats[BlockID];

BlockStats.NumInstances++;

// BLOCKINFO is a special part of the stream.
bool DumpRecords = O.hasValue();
if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
1
Assuming 'BlockID' is not equal to BLOCKINFO_BLOCK_ID→
2
←
Taking false branch→
  if (O)
    O->OS << Indent << "<BLOCKINFO_BLOCK/>\n";
  Expected<Optional<BitstreamBlockInfo>> MaybeNewBlockInfo =
      Stream.ReadBlockInfoBlock(/*ReadBlockInfoNames=*/true);
  if (!MaybeNewBlockInfo)
    return MaybeNewBlockInfo.takeError();
  Optional<BitstreamBlockInfo> NewBlockInfo =
      std::move(MaybeNewBlockInfo.get());
  if (!NewBlockInfo)
    return reportError("Malformed BlockInfoBlock");
  BlockInfo = std::move(*NewBlockInfo);
  if (Error Err = Stream.JumpToBit(BlockBitStart))
    return Err;
  // It's not really interesting to dump the contents of the blockinfo
  // block.
  DumpRecords = false;
}

unsigned NumWords = 0;
if (Error Err = Stream.EnterSubBlock(BlockID, &NumWords))
3
←
Assuming the condition is false→
4
←
Taking false branch→
  return Err;

// Keep it for later, when we see a MODULE_HASH record
uint64_t BlockEntryPos = Stream.getCurrentByteNo();

Optional<const char *> BlockName = None;
if (DumpRecords) {
5
←
Assuming 'DumpRecords' is false→
6
←
Taking false branch→
  O->OS << Indent << "<";
  if ((BlockName = GetBlockName(BlockID, BlockInfo, CurStreamType)))
    O->OS << *BlockName;
  else
    O->OS << "UnknownBlock" << BlockID;

  if (!O->Symbolic && BlockName)
    O->OS << " BlockID=" << BlockID;

  O->OS << " NumWords=" << NumWords
        << " BlockCodeSize=" << Stream.getAbbrevIDWidth() << ">\n";
}

SmallVector<uint64_t, 64> Record;

// Keep the offset to the metadata index if seen.
uint64_t MetadataIndexOffset = 0;

// Read all the records for this block.
while (1) {
7
←
Loop condition is true.  Entering loop body→
  if (Stream.AtEndOfStream())
8
←
Taking false branch→
    return reportError("Premature end of bitstream");

  uint64_t RecordStartBit = Stream.GetCurrentBitNo();

  Expected<BitstreamEntry> MaybeEntry =
      Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
9
←
Calling 'BitstreamCursor::advance'→
  if (!MaybeEntry)
    return MaybeEntry.takeError();
  BitstreamEntry Entry = MaybeEntry.get();

  switch (Entry.Kind) {
  case BitstreamEntry::Error:
    return reportError("malformed bitcode file");
  case BitstreamEntry::EndBlock: {
    uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
    BlockStats.NumBits += BlockBitEnd - BlockBitStart;
    if (DumpRecords) {
      O->OS << Indent << "</";
      if (BlockName)
        O->OS << *BlockName << ">\n";
      else
        O->OS << "UnknownBlock" << BlockID << ">\n";
    }
    return Error::success();
  }

  case BitstreamEntry::SubBlock: {
    uint64_t SubBlockBitStart = Stream.GetCurrentBitNo();
    if (Error E = parseBlock(Entry.ID, IndentLevel + 1, O, CheckHash))
      return E;
    ++BlockStats.NumSubBlocks;
    uint64_t SubBlockBitEnd = Stream.GetCurrentBitNo();

    // Don't include subblock sizes in the size of this block.
    BlockBitStart += SubBlockBitEnd - SubBlockBitStart;
    continue;
  }
  case BitstreamEntry::Record:
    // The interesting case.
    break;
  }

  if (Entry.ID == bitc::DEFINE_ABBREV) {
    if (Error Err = Stream.ReadAbbrevRecord())
      return Err;
    ++BlockStats.NumAbbrevs;
    continue;
  }

  Record.clear();

  ++BlockStats.NumRecords;

  StringRef Blob;
  uint64_t CurrentRecordPos = Stream.GetCurrentBitNo();
  Expected<unsigned> MaybeCode = Stream.readRecord(Entry.ID, Record, &Blob);
  if (!MaybeCode)
    return MaybeCode.takeError();
  unsigned Code = MaybeCode.get();

  // Increment the # occurrences of this code.
  if (BlockStats.CodeFreq.size() <= Code)
    BlockStats.CodeFreq.resize(Code + 1);
  BlockStats.CodeFreq[Code].NumInstances++;
  BlockStats.CodeFreq[Code].TotalBits +=
      Stream.GetCurrentBitNo() - RecordStartBit;
  if (Entry.ID != bitc::UNABBREV_RECORD) {
    BlockStats.CodeFreq[Code].NumAbbrev++;
    ++BlockStats.NumAbbreviatedRecords;
  }

  if (DumpRecords) {
    O->OS << Indent << "  <";
    Optional<const char *> CodeName =
        GetCodeName(Code, BlockID, BlockInfo, CurStreamType);
    if (CodeName)
      O->OS << *CodeName;
    else
      O->OS << "UnknownCode" << Code;
    if (!O->Symbolic && CodeName)
      O->OS << " codeid=" << Code;
    const BitCodeAbbrev *Abbv = nullptr;
    if (Entry.ID != bitc::UNABBREV_RECORD) {
      Abbv = Stream.getAbbrev(Entry.ID);
      O->OS << " abbrevid=" << Entry.ID;
    }

    for (unsigned i = 0, e = Record.size(); i != e; ++i)
      O->OS << " op" << i << "=" << (int64_t)Record[i];

    // If we found a metadata index, let's verify that we had an offset
    // before and validate its forward reference offset was correct!
    if (BlockID == bitc::METADATA_BLOCK_ID) {
      if (Code == bitc::METADATA_INDEX_OFFSET) {
        if (Record.size() != 2)
          O->OS << "(Invalid record)";
        else {
          auto Offset = Record[0] + (Record[1] << 32);
          MetadataIndexOffset = Stream.GetCurrentBitNo() + Offset;
        }
      }
      if (Code == bitc::METADATA_INDEX) {
        O->OS << " (offset ";
        if (MetadataIndexOffset == RecordStartBit)
          O->OS << "match)";
        else
          O->OS << "mismatch: " << MetadataIndexOffset << " vs "
                << RecordStartBit << ")";
      }
    }

    // If we found a module hash, let's verify that it matches!
    if (BlockID == bitc::MODULE_BLOCK_ID && Code == bitc::MODULE_CODE_HASH &&
        CheckHash.hasValue()) {
      if (Record.size() != 5)
        O->OS << " (invalid)";
      else {
        // Recompute the hash and compare it to the one in the bitcode
        SHA1 Hasher;
        StringRef Hash;
        Hasher.update(*CheckHash);
        {
          int BlockSize = (CurrentRecordPos / 8) - BlockEntryPos;
          auto Ptr = Stream.getPointerToByte(BlockEntryPos, BlockSize);
          Hasher.update(ArrayRef<uint8_t>(Ptr, BlockSize));
          Hash = Hasher.result();
        }
        SmallString<20> RecordedHash;
        RecordedHash.resize(20);
        int Pos = 0;
        for (auto &Val : Record) {
          assert(!(Val >> 32) && "Unexpected high bits set")((!(Val >> 32) && "Unexpected high bits set") ?
 static_cast<void> (0) : __assert_fail ("!(Val >> 32) && \"Unexpected high bits set\""
, "/build/llvm-toolchain-snapshot-10~svn374877/lib/Bitcode/Reader/BitcodeAnalyzer.cpp"
, 917, __PRETTY_FUNCTION__));
          RecordedHash[Pos++] = (Val >> 24) & 0xFF;
          RecordedHash[Pos++] = (Val >> 16) & 0xFF;
          RecordedHash[Pos++] = (Val >> 8) & 0xFF;
          RecordedHash[Pos++] = (Val >> 0) & 0xFF;
        }
        if (Hash == RecordedHash)
          O->OS << " (match)";
        else
          O->OS << " (!mismatch!)";
      }
    }

    O->OS << "/>";

    if (Abbv) {
      for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i != e; ++i) {
        const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
        if (!Op.isEncoding() || Op.getEncoding() != BitCodeAbbrevOp::Array)
          continue;
        assert(i + 2 == e && "Array op not second to last")((i + 2 == e && "Array op not second to last") ? static_cast
<void> (0) : __assert_fail ("i + 2 == e && \"Array op not second to last\""
, "/build/llvm-toolchain-snapshot-10~svn374877/lib/Bitcode/Reader/BitcodeAnalyzer.cpp"
, 937, __PRETTY_FUNCTION__));
        std::string Str;
        bool ArrayIsPrintable = true;
        for (unsigned j = i - 1, je = Record.size(); j != je; ++j) {
          if (!isPrint(static_cast<unsigned char>(Record[j]))) {
            ArrayIsPrintable = false;
            break;
          }
          Str += (char)Record[j];
        }
        if (ArrayIsPrintable)
          O->OS << " record string = '" << Str << "'";
        break;
      }
    }

    if (Blob.data()) {
      if (canDecodeBlob(Code, BlockID)) {
        if (Error E = decodeMetadataStringsBlob(Indent, Record, Blob, O->OS))
          return E;
      } else {
        O->OS << " blob data = ";
        if (O->ShowBinaryBlobs) {
          O->OS << "'";
          O->OS.write_escaped(Blob, /*hex=*/true) << "'";
        } else {
          bool BlobIsPrintable = true;
          for (unsigned i = 0, e = Blob.size(); i != e; ++i)
            if (!isPrint(static_cast<unsigned char>(Blob[i]))) {
              BlobIsPrintable = false;
              break;
            }

          if (BlobIsPrintable)
            O->OS << "'" << Blob << "'";
          else
            O->OS << "unprintable, " << Blob.size() << " bytes.";
        }
      }
    }

    O->OS << "\n";
  }

  // Make sure that we can skip the current record.
  if (Error Err = Stream.JumpToBit(CurrentRecordPos))
    return Err;
  if (Expected<unsigned> Skipped = Stream.skipRecord(Entry.ID))
    ; // Do nothing.
  else
    return Skipped.takeError();
}
989}


←

/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Bitstream/BitstreamReader.h

→

1//===- BitstreamReader.h - Low-level bitstream reader interface -*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This header defines the BitstreamReader class.  This class can be used to
10// read an arbitrary bitstream, regardless of its contents.
11//
12//===----------------------------------------------------------------------===//

14#ifndef LLVM_BITSTREAM_BITSTREAMREADER_H
15#define LLVM_BITSTREAM_BITSTREAMREADER_H

17#include "llvm/ADT/ArrayRef.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/Bitstream/BitCodes.h"
20#include "llvm/Support/Endian.h"
21#include "llvm/Support/ErrorHandling.h"
22#include "llvm/Support/MathExtras.h"
23#include "llvm/Support/MemoryBuffer.h"
24#include <algorithm>
25#include <cassert>
26#include <climits>
27#include <cstddef>
28#include <cstdint>
29#include <memory>
30#include <string>
31#include <utility>
32#include <vector>

34namespace llvm {

36/// This class maintains the abbreviations read from a block info block.
37class BitstreamBlockInfo {
38public:
/// This contains information emitted to BLOCKINFO_BLOCK blocks. These
/// describe abbreviations that all blocks of the specified ID inherit.
struct BlockInfo {
  unsigned BlockID;
  std::vector<std::shared_ptr<BitCodeAbbrev>> Abbrevs;
  std::string Name;
  std::vector<std::pair<unsigned, std::string>> RecordNames;
};

48private:
std::vector<BlockInfo> BlockInfoRecords;

51public:
/// If there is block info for the specified ID, return it, otherwise return
/// null.
const BlockInfo *getBlockInfo(unsigned BlockID) const {
  // Common case, the most recent entry matches BlockID.
  if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
    return &BlockInfoRecords.back();

  for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
       i != e; ++i)
    if (BlockInfoRecords[i].BlockID == BlockID)
      return &BlockInfoRecords[i];
  return nullptr;
}

BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
  if (const BlockInfo *BI = getBlockInfo(BlockID))
    return *const_cast<BlockInfo*>(BI);

  // Otherwise, add a new record.
  BlockInfoRecords.emplace_back();
  BlockInfoRecords.back().BlockID = BlockID;
  return BlockInfoRecords.back();
}
75};

77/// This represents a position within a bitstream. There may be multiple
78/// independent cursors reading within one bitstream, each maintaining their
79/// own local state.
80class SimpleBitstreamCursor {
ArrayRef<uint8_t> BitcodeBytes;
size_t NextChar = 0;

84public:
/// This is the current data we have pulled from the stream but have not
/// returned to the client. This is specifically and intentionally defined to
/// follow the word size of the host machine for efficiency. We use word_t in
/// places that are aware of this to make it perfectly explicit what is going
/// on.
using word_t = size_t;

92private:
word_t CurWord = 0;

/// This is the number of bits in CurWord that are valid. This is always from
/// [0...bits_of(size_t)-1] inclusive.
unsigned BitsInCurWord = 0;

99public:
static const constexpr size_t MaxChunkSize = sizeof(word_t) * 8;

SimpleBitstreamCursor() = default;
explicit SimpleBitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
    : BitcodeBytes(BitcodeBytes) {}
explicit SimpleBitstreamCursor(StringRef BitcodeBytes)
    : BitcodeBytes(arrayRefFromStringRef(BitcodeBytes)) {}
explicit SimpleBitstreamCursor(MemoryBufferRef BitcodeBytes)
    : SimpleBitstreamCursor(BitcodeBytes.getBuffer()) {}

bool canSkipToPos(size_t pos) const {
  // pos can be skipped to if it is a valid address or one byte past the end.
  return pos <= BitcodeBytes.size();
}

bool AtEndOfStream() {
  return BitsInCurWord == 0 && BitcodeBytes.size() <= NextChar;
}

/// Return the bit # of the bit we are reading.
uint64_t GetCurrentBitNo() const {
  return NextChar*CHAR_BIT8 - BitsInCurWord;
}

// Return the byte # of the current bit.
uint64_t getCurrentByteNo() const { return GetCurrentBitNo() / 8; }

ArrayRef<uint8_t> getBitcodeBytes() const { return BitcodeBytes; }

/// Reset the stream to the specified bit number.
Error JumpToBit(uint64_t BitNo) {
  size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
  unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
  assert(canSkipToPos(ByteNo) && "Invalid location")((canSkipToPos(ByteNo) && "Invalid location") ? static_cast
<void> (0) : __assert_fail ("canSkipToPos(ByteNo) && \"Invalid location\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Bitstream/BitstreamReader.h"
, 133, __PRETTY_FUNCTION__));

  // Move the cursor to the right word.
  NextChar = ByteNo;
  BitsInCurWord = 0;

  // Skip over any bits that are already consumed.
  if (WordBitNo) {
    if (Expected<word_t> Res = Read(WordBitNo))
      return Error::success();
    else
      return Res.takeError();
  }

  return Error::success();
}

/// Get a pointer into the bitstream at the specified byte offset.
const uint8_t *getPointerToByte(uint64_t ByteNo, uint64_t NumBytes) {
  return BitcodeBytes.data() + ByteNo;
}

/// Get a pointer into the bitstream at the specified bit offset.
///
/// The bit offset must be on a byte boundary.
const uint8_t *getPointerToBit(uint64_t BitNo, uint64_t NumBytes) {
  assert(!(BitNo % 8) && "Expected bit on byte boundary")((!(BitNo % 8) && "Expected bit on byte boundary") ? static_cast
<void> (0) : __assert_fail ("!(BitNo % 8) && \"Expected bit on byte boundary\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Bitstream/BitstreamReader.h"
, 159, __PRETTY_FUNCTION__));
  return getPointerToByte(BitNo / 8, NumBytes);
}

Error fillCurWord() {
  if (NextChar >= BitcodeBytes.size())
    return createStringError(std::errc::io_error,
                             "Unexpected end of file reading %u of %u bytes",
                             NextChar, BitcodeBytes.size());

  // Read the next word from the stream.
  const uint8_t *NextCharPtr = BitcodeBytes.data() + NextChar;
  unsigned BytesRead;
  if (BitcodeBytes.size() >= NextChar + sizeof(word_t)) {
    BytesRead = sizeof(word_t);
    CurWord =
        support::endian::read<word_t, support::little, support::unaligned>(
            NextCharPtr);
  } else {
    // Short read.
    BytesRead = BitcodeBytes.size() - NextChar;
    CurWord = 0;
    for (unsigned B = 0; B != BytesRead; ++B)
      CurWord |= uint64_t(NextCharPtr[B]) << (B * 8);
  }
  NextChar += BytesRead;
  BitsInCurWord = BytesRead * 8;
  return Error::success();
}

Expected<word_t> Read(unsigned NumBits) {
  static const unsigned BitsInWord = MaxChunkSize;

  assert(NumBits && NumBits <= BitsInWord &&((NumBits && NumBits <= BitsInWord && "Cannot return zero or more than BitsInWord bits!"
) ? static_cast<void> (0) : __assert_fail ("NumBits && NumBits <= BitsInWord && \"Cannot return zero or more than BitsInWord bits!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Bitstream/BitstreamReader.h"
, 193, __PRETTY_FUNCTION__))
14
←
Assuming 'NumBits' is not equal to 0→
15
←
Assuming 'NumBits' is <= 'BitsInWord'→
16
←
'?' condition is true→
         "Cannot return zero or more than BitsInWord bits!")((NumBits && NumBits <= BitsInWord && "Cannot return zero or more than BitsInWord bits!"
) ? static_cast<void> (0) : __assert_fail ("NumBits && NumBits <= BitsInWord && \"Cannot return zero or more than BitsInWord bits!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Bitstream/BitstreamReader.h"
, 193, __PRETTY_FUNCTION__));

  static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
17
←
'?' condition is true→

  // If the field is fully contained by CurWord, return it quickly.
  if (BitsInCurWord >= NumBits) {
18
←
Assuming 'NumBits' is > field 'BitsInCurWord'→
19
←
Taking false branch→
    word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));

    // Use a mask to avoid undefined behavior.
    CurWord >>= (NumBits & Mask);

    BitsInCurWord -= NumBits;
    return R;
  }

  word_t R = BitsInCurWord19.1
Field 'BitsInCurWord' is not equal to 0
1
Field 'BitsInCurWord' is not equal to 0
1
Field 'BitsInCurWord' is not equal to 0
 ? CurWord : 0;
20
←
'?' condition is true→
  unsigned BitsLeft = NumBits - BitsInCurWord;

  if (Error fillResult = fillCurWord())
21
←
Calling 'Error::operator bool'→
23
←
Returning from 'Error::operator bool'→
24
←
Taking false branch→
    return std::move(fillResult);

  // If we run out of data, abort.
  if (BitsLeft > BitsInCurWord)
25
←
Assuming 'BitsLeft' is <= field 'BitsInCurWord'→
26
←
Taking false branch→
    return createStringError(std::errc::io_error,
                             "Unexpected end of file reading %u of %u bits",
                             BitsInCurWord, BitsLeft);

  word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
27
←
The result of the right shift is undefined due to shifting by '64', which is greater or equal to the width of type 'llvm::SimpleBitstreamCursor::word_t'

  // Use a mask to avoid undefined behavior.
  CurWord >>= (BitsLeft & Mask);

  BitsInCurWord -= BitsLeft;

  R |= R2 << (NumBits - BitsLeft);

  return R;
}

Expected<uint32_t> ReadVBR(unsigned NumBits) {
  Expected<unsigned> MaybeRead = Read(NumBits);
  if (!MaybeRead)
    return MaybeRead;
  uint32_t Piece = MaybeRead.get();

  if ((Piece & (1U << (NumBits-1))) == 0)
    return Piece;

  uint32_t Result = 0;
  unsigned NextBit = 0;
  while (true) {
    Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;

    if ((Piece & (1U << (NumBits-1))) == 0)
      return Result;

    NextBit += NumBits-1;
    MaybeRead = Read(NumBits);
    if (!MaybeRead)
      return MaybeRead;
    Piece = MaybeRead.get();
  }
}

// Read a VBR that may have a value up to 64-bits in size. The chunk size of
// the VBR must still be <= 32 bits though.
Expected<uint64_t> ReadVBR64(unsigned NumBits) {
  Expected<uint64_t> MaybeRead = Read(NumBits);
  if (!MaybeRead)
    return MaybeRead;
  uint32_t Piece = MaybeRead.get();

  if ((Piece & (1U << (NumBits-1))) == 0)
    return uint64_t(Piece);

  uint64_t Result = 0;
  unsigned NextBit = 0;
  while (true) {
    Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;

    if ((Piece & (1U << (NumBits-1))) == 0)
      return Result;

    NextBit += NumBits-1;
    MaybeRead = Read(NumBits);
    if (!MaybeRead)
      return MaybeRead;
    Piece = MaybeRead.get();
  }
}

void SkipToFourByteBoundary() {
  // If word_t is 64-bits and if we've read less than 32 bits, just dump
  // the bits we have up to the next 32-bit boundary.
  if (sizeof(word_t) > 4 &&
      BitsInCurWord >= 32) {
    CurWord >>= BitsInCurWord-32;
    BitsInCurWord = 32;
    return;
  }

  BitsInCurWord = 0;
}

/// Return the size of the stream in bytes.
size_t SizeInBytes() const { return BitcodeBytes.size(); }

/// Skip to the end of the file.
void skipToEnd() { NextChar = BitcodeBytes.size(); }
302};

304/// When advancing through a bitstream cursor, each advance can discover a few
305/// different kinds of entries:
306struct BitstreamEntry {
enum {
  Error,    // Malformed bitcode was found.
  EndBlock, // We've reached the end of the current block, (or the end of the
            // file, which is treated like a series of EndBlock records.
  SubBlock, // This is the start of a new subblock of a specific ID.
  Record    // This is a record with a specific AbbrevID.
} Kind;

unsigned ID;

static BitstreamEntry getError() {
  BitstreamEntry E; E.Kind = Error; return E;
}

static BitstreamEntry getEndBlock() {
  BitstreamEntry E; E.Kind = EndBlock; return E;
}

static BitstreamEntry getSubBlock(unsigned ID) {
  BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
}

static BitstreamEntry getRecord(unsigned AbbrevID) {
  BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
}
332};

334/// This represents a position within a bitcode file, implemented on top of a
335/// SimpleBitstreamCursor.
336///
337/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
338/// be passed by value.
339class BitstreamCursor : SimpleBitstreamCursor {
// This is the declared size of code values used for the current block, in
// bits.
unsigned CurCodeSize = 2;

/// Abbrevs installed at in this block.
std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs;

struct Block {
  unsigned PrevCodeSize;
  std::vector<std::shared_ptr<BitCodeAbbrev>> PrevAbbrevs;

  explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
};

/// This tracks the codesize of parent blocks.
SmallVector<Block, 8> BlockScope;

BitstreamBlockInfo *BlockInfo = nullptr;

359public:
static const size_t MaxChunkSize = sizeof(word_t) * 8;

BitstreamCursor() = default;
explicit BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
    : SimpleBitstreamCursor(BitcodeBytes) {}
explicit BitstreamCursor(StringRef BitcodeBytes)
    : SimpleBitstreamCursor(BitcodeBytes) {}
explicit BitstreamCursor(MemoryBufferRef BitcodeBytes)
    : SimpleBitstreamCursor(BitcodeBytes) {}

using SimpleBitstreamCursor::AtEndOfStream;
using SimpleBitstreamCursor::canSkipToPos;
using SimpleBitstreamCursor::fillCurWord;
using SimpleBitstreamCursor::getBitcodeBytes;
using SimpleBitstreamCursor::GetCurrentBitNo;
using SimpleBitstreamCursor::getCurrentByteNo;
using SimpleBitstreamCursor::getPointerToByte;
using SimpleBitstreamCursor::JumpToBit;
using SimpleBitstreamCursor::Read;
using SimpleBitstreamCursor::ReadVBR;
using SimpleBitstreamCursor::ReadVBR64;
using SimpleBitstreamCursor::SizeInBytes;
using SimpleBitstreamCursor::skipToEnd;

/// Return the number of bits used to encode an abbrev #.
unsigned getAbbrevIDWidth() const { return CurCodeSize; }

/// Flags that modify the behavior of advance().
enum {
  /// If this flag is used, the advance() method does not automatically pop
  /// the block scope when the end of a block is reached.
  AF_DontPopBlockAtEnd = 1,

  /// If this flag is used, abbrev entries are returned just like normal
  /// records.
  AF_DontAutoprocessAbbrevs = 2
};

/// Advance the current bitstream, returning the next entry in the stream.
Expected<BitstreamEntry> advance(unsigned Flags = 0) {
  while (true) {
10
←
Loop condition is true.  Entering loop body→
    if (AtEndOfStream())
11
←
Taking false branch→
      return BitstreamEntry::getError();

    Expected<unsigned> MaybeCode = ReadCode();
12
←
Calling 'BitstreamCursor::ReadCode'→
    if (!MaybeCode)
      return MaybeCode.takeError();
    unsigned Code = MaybeCode.get();

    if (Code == bitc::END_BLOCK) {
      // Pop the end of the block unless Flags tells us not to.
      if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
        return BitstreamEntry::getError();
      return BitstreamEntry::getEndBlock();
    }

    if (Code == bitc::ENTER_SUBBLOCK) {
      if (Expected<unsigned> MaybeSubBlock = ReadSubBlockID())
        return BitstreamEntry::getSubBlock(MaybeSubBlock.get());
      else
        return MaybeSubBlock.takeError();
    }

    if (Code == bitc::DEFINE_ABBREV &&
        !(Flags & AF_DontAutoprocessAbbrevs)) {
      // We read and accumulate abbrev's, the client can't do anything with
      // them anyway.
      if (Error Err = ReadAbbrevRecord())
        return std::move(Err);
      continue;
    }

    return BitstreamEntry::getRecord(Code);
  }
}

/// This is a convenience function for clients that don't expect any
/// subblocks. This just skips over them automatically.
Expected<BitstreamEntry> advanceSkippingSubblocks(unsigned Flags = 0) {
  while (true) {
    // If we found a normal entry, return it.
    Expected<BitstreamEntry> MaybeEntry = advance(Flags);
    if (!MaybeEntry)
      return MaybeEntry;
    BitstreamEntry Entry = MaybeEntry.get();

    if (Entry.Kind != BitstreamEntry::SubBlock)
      return Entry;

    // If we found a sub-block, just skip over it and check the next entry.
    if (Error Err = SkipBlock())
      return std::move(Err);
  }
}

Expected<unsigned> ReadCode() { return Read(CurCodeSize); }
13
←
Calling 'SimpleBitstreamCursor::Read'→

// Block header:
//    [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]

/// Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
Expected<unsigned> ReadSubBlockID() { return ReadVBR(bitc::BlockIDWidth); }

/// Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body
/// of this block.
Error SkipBlock() {
  // Read and ignore the codelen value.
  if (Expected<uint32_t> Res = ReadVBR(bitc::CodeLenWidth))
    ; // Since we are skipping this block, we don't care what code widths are
      // used inside of it.
  else
    return Res.takeError();

  SkipToFourByteBoundary();
  Expected<unsigned> MaybeNum = Read(bitc::BlockSizeWidth);
  if (!MaybeNum)
    return MaybeNum.takeError();
  size_t NumFourBytes = MaybeNum.get();

  // Check that the block wasn't partially defined, and that the offset isn't
  // bogus.
  size_t SkipTo = GetCurrentBitNo() + NumFourBytes * 4 * 8;
  if (AtEndOfStream())
    return createStringError(std::errc::illegal_byte_sequence,
                             "can't skip block: already at end of stream");
  if (!canSkipToPos(SkipTo / 8))
    return createStringError(std::errc::illegal_byte_sequence,
                             "can't skip to bit %zu from %" PRIu64"l" "u", SkipTo,
                             GetCurrentBitNo());

  if (Error Res = JumpToBit(SkipTo))
    return Res;

  return Error::success();
}

/// Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
Error EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);

bool ReadBlockEnd() {
  if (BlockScope.empty()) return true;

  // Block tail:
  //    [END_BLOCK, <align4bytes>]
  SkipToFourByteBoundary();

  popBlockScope();
  return false;
}

510private:
void popBlockScope() {
  CurCodeSize = BlockScope.back().PrevCodeSize;

  CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
  BlockScope.pop_back();
}

//===--------------------------------------------------------------------===//
// Record Processing
//===--------------------------------------------------------------------===//

522public:
/// Return the abbreviation for the specified AbbrevId.
const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
  unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
  if (AbbrevNo >= CurAbbrevs.size())
    report_fatal_error("Invalid abbrev number");
  return CurAbbrevs[AbbrevNo].get();
}

/// Read the current record and discard it, returning the code for the record.
Expected<unsigned> skipRecord(unsigned AbbrevID);

Expected<unsigned> readRecord(unsigned AbbrevID,
                              SmallVectorImpl<uint64_t> &Vals,
                              StringRef *Blob = nullptr);

//===--------------------------------------------------------------------===//
// Abbrev Processing
//===--------------------------------------------------------------------===//
Error ReadAbbrevRecord();

/// Read and return a block info block from the bitstream. If an error was
/// encountered, return None.
///
/// \param ReadBlockInfoNames Whether to read block/record name information in
/// the BlockInfo block. Only llvm-bcanalyzer uses this.
Expected<Optional<BitstreamBlockInfo>>
ReadBlockInfoBlock(bool ReadBlockInfoNames = false);

/// Set the block info to be used by this BitstreamCursor to interpret
/// abbreviated records.
void setBlockInfo(BitstreamBlockInfo *BI) { BlockInfo = BI; }
554};

556} // end llvm namespace

558#endif // LLVM_BITSTREAM_BITSTREAMREADER_H

←

/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h

1//===- llvm/Support/Error.h - Recoverable error handling --------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines an API used to report recoverable errors.
10//
11//===----------------------------------------------------------------------===//
12 
13#ifndef LLVM_SUPPORT_ERROR_H
14#define LLVM_SUPPORT_ERROR_H
15 
16#include "llvm-c/Error.h"
17#include "llvm/ADT/STLExtras.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringExtras.h"
20#include "llvm/ADT/Twine.h"
21#include "llvm/Config/abi-breaking.h"
22#include "llvm/Support/AlignOf.h"
23#include "llvm/Support/Compiler.h"
24#include "llvm/Support/Debug.h"
25#include "llvm/Support/ErrorHandling.h"
26#include "llvm/Support/ErrorOr.h"
27#include "llvm/Support/Format.h"
28#include "llvm/Support/raw_ostream.h"
29#include <algorithm>
30#include <cassert>
31#include <cstdint>
32#include <cstdlib>
33#include <functional>
34#include <memory>
35#include <new>
36#include <string>
37#include <system_error>
38#include <type_traits>
39#include <utility>
40#include <vector>
41 
42namespace llvm {
43 
44class ErrorSuccess;
45 
46/// Base class for error info classes. Do not extend this directly: Extend
47/// the ErrorInfo template subclass instead.
48class ErrorInfoBase {
49public:
50  virtual ~ErrorInfoBase() = default;
51 
52  /// Print an error message to an output stream.
53  virtual void log(raw_ostream &OS) const = 0;
54 
55  /// Return the error message as a string.
56  virtual std::string message() const {
57    std::string Msg;
58    raw_string_ostream OS(Msg);
59    log(OS);
60    return OS.str();
61  }
62 
63  /// Convert this error to a std::error_code.
64  ///
65  /// This is a temporary crutch to enable interaction with code still
66  /// using std::error_code. It will be removed in the future.
67  virtual std::error_code convertToErrorCode() const = 0;
68 
69  // Returns the class ID for this type.
70  static const void *classID() { return &ID; }
71 
72  // Returns the class ID for the dynamic type of this ErrorInfoBase instance.
73  virtual const void *dynamicClassID() const = 0;
74 
75  // Check whether this instance is a subclass of the class identified by
76  // ClassID.
77  virtual bool isA(const void *const ClassID) const {
78    return ClassID == classID();
79  }
80 
81  // Check whether this instance is a subclass of ErrorInfoT.
82  template <typename ErrorInfoT> bool isA() const {
83    return isA(ErrorInfoT::classID());
84  }
85 
86private:
87  virtual void anchor();
88 
89  static char ID;
90};
91 
92/// Lightweight error class with error context and mandatory checking.
93///
94/// Instances of this class wrap a ErrorInfoBase pointer. Failure states
95/// are represented by setting the pointer to a ErrorInfoBase subclass
96/// instance containing information describing the failure. Success is
97/// represented by a null pointer value.
98///
99/// Instances of Error also contains a 'Checked' flag, which must be set
100/// before the destructor is called, otherwise the destructor will trigger a
101/// runtime error. This enforces at runtime the requirement that all Error
102/// instances be checked or returned to the caller.
103///
104/// There are two ways to set the checked flag, depending on what state the
105/// Error instance is in. For Error instances indicating success, it
106/// is sufficient to invoke the boolean conversion operator. E.g.:
107///
108///   @code{.cpp}
109///   Error foo(<...>);
110///
111///   if (auto E = foo(<...>))
112///     return E; // <- Return E if it is in the error state.
113///   // We have verified that E was in the success state. It can now be safely
114///   // destroyed.
115///   @endcode
116///
117/// A success value *can not* be dropped. For example, just calling 'foo(<...>)'
118/// without testing the return value will raise a runtime error, even if foo
119/// returns success.
120///
121/// For Error instances representing failure, you must use either the
122/// handleErrors or handleAllErrors function with a typed handler. E.g.:
123///
124///   @code{.cpp}
125///   class MyErrorInfo : public ErrorInfo<MyErrorInfo> {
126///     // Custom error info.
127///   };
128///
129///   Error foo(<...>) { return make_error<MyErrorInfo>(...); }
130///
131///   auto E = foo(<...>); // <- foo returns failure with MyErrorInfo.
132///   auto NewE =
133///     handleErrors(E,
134///       [](const MyErrorInfo &M) {
135///         // Deal with the error.
136///       },
137///       [](std::unique_ptr<OtherError> M) -> Error {
138///         if (canHandle(*M)) {
139///           // handle error.
140///           return Error::success();
141///         }
142///         // Couldn't handle this error instance. Pass it up the stack.
143///         return Error(std::move(M));
144///       );
145///   // Note - we must check or return NewE in case any of the handlers
146///   // returned a new error.
147///   @endcode
148///
149/// The handleAllErrors function is identical to handleErrors, except
150/// that it has a void return type, and requires all errors to be handled and
151/// no new errors be returned. It prevents errors (assuming they can all be
152/// handled) from having to be bubbled all the way to the top-level.
153///
154/// *All* Error instances must be checked before destruction, even if
155/// they're moved-assigned or constructed from Success values that have already
156/// been checked. This enforces checking through all levels of the call stack.
157class LLVM_NODISCARD[[clang::warn_unused_result]] Error {
158  // Both ErrorList and FileError need to be able to yank ErrorInfoBase
159  // pointers out of this class to add to the error list.
160  friend class ErrorList;
161  friend class FileError;
162 
163  // handleErrors needs to be able to set the Checked flag.
164  template <typename... HandlerTs>
165  friend Error handleErrors(Error E, HandlerTs &&... Handlers);
166 
167  // Expected<T> needs to be able to steal the payload when constructed from an
168  // error.
169  template <typename T> friend class Expected;
170 
171  // wrap needs to be able to steal the payload.
172  friend LLVMErrorRef wrap(Error);
173 
174protected:
175  /// Create a success value. Prefer using 'Error::success()' for readability
176  Error() {
177    setPtr(nullptr);
178    setChecked(false);
179  }
180 
181public:
182  /// Create a success value.
183  static ErrorSuccess success();
184 
185  // Errors are not copy-constructable.
186  Error(const Error &Other) = delete;
187 
188  /// Move-construct an error value. The newly constructed error is considered
189  /// unchecked, even if the source error had been checked. The original error
190  /// becomes a checked Success value, regardless of its original state.
191  Error(Error &&Other) {
192    setChecked(true);
193    *this = std::move(Other);
194  }
195 
196  /// Create an error value. Prefer using the 'make_error' function, but
197  /// this constructor can be useful when "re-throwing" errors from handlers.
198  Error(std::unique_ptr<ErrorInfoBase> Payload) {
199    setPtr(Payload.release());
200    setChecked(false);
201  }
202 
203  // Errors are not copy-assignable.
204  Error &operator=(const Error &Other) = delete;
205 
206  /// Move-assign an error value. The current error must represent success, you
207  /// you cannot overwrite an unhandled error. The current error is then
208  /// considered unchecked. The source error becomes a checked success value,
209  /// regardless of its original state.
210  Error &operator=(Error &&Other) {
211    // Don't allow overwriting of unchecked values.
212    assertIsChecked();
213    setPtr(Other.getPtr());
214 
215    // This Error is unchecked, even if the source error was checked.
216    setChecked(false);
217 
218    // Null out Other's payload and set its checked bit.
219    Other.setPtr(nullptr);
220    Other.setChecked(true);
221 
222    return *this;
223  }
224 
225  /// Destroy a Error. Fails with a call to abort() if the error is
226  /// unchecked.
227  ~Error() {
228    assertIsChecked();
229    delete getPtr();
230  }
231 
232  /// Bool conversion. Returns true if this Error is in a failure state,
233  /// and false if it is in an accept state. If the error is in a Success state
234  /// it will be considered checked.
235  explicit operator bool() {
236    setChecked(getPtr() == nullptr);
237    return getPtr() != nullptr;
22
←
Returning zero, which participates in a condition later→
238  }
239 
240  /// Check whether one error is a subclass of another.
241  template <typename ErrT> bool isA() const {
242    return getPtr() && getPtr()->isA(ErrT::classID());
243  }
244 
245  /// Returns the dynamic class id of this error, or null if this is a success
246  /// value.
247  const void* dynamicClassID() const {
248    if (!getPtr())
249      return nullptr;
250    return getPtr()->dynamicClassID();
251  }
252 
253private:
254#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
255  // assertIsChecked() happens very frequently, but under normal circumstances
256  // is supposed to be a no-op.  So we want it to be inlined, but having a bunch
257  // of debug prints can cause the function to be too large for inlining.  So
258  // it's important that we define this function out of line so that it can't be
259  // inlined.
260  LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
261  void fatalUncheckedError() const;
262#endif
263 
264  void assertIsChecked() {
265#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
266    if (LLVM_UNLIKELY(!getChecked() || getPtr())__builtin_expect((bool)(!getChecked() || getPtr()), false))
267      fatalUncheckedError();
268#endif
269  }
270 
271  ErrorInfoBase *getPtr() const {
272    return reinterpret_cast<ErrorInfoBase*>(
273             reinterpret_cast<uintptr_t>(Payload) &
274             ~static_cast<uintptr_t>(0x1));
275  }
276 
277  void setPtr(ErrorInfoBase *EI) {
278#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
279    Payload = reinterpret_cast<ErrorInfoBase*>(
280                (reinterpret_cast<uintptr_t>(EI) &
281                 ~static_cast<uintptr_t>(0x1)) |
282                (reinterpret_cast<uintptr_t>(Payload) & 0x1));
283#else
284    Payload = EI;
285#endif
286  }
287 
288  bool getChecked() const {
289#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
290    return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
291#else
292    return true;
293#endif
294  }
295 
296  void setChecked(bool V) {
297    Payload = reinterpret_cast<ErrorInfoBase*>(
298                (reinterpret_cast<uintptr_t>(Payload) &
299                  ~static_cast<uintptr_t>(0x1)) |
300                  (V ? 0 : 1));
301  }
302 
303  std::unique_ptr<ErrorInfoBase> takePayload() {
304    std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
305    setPtr(nullptr);
306    setChecked(true);
307    return Tmp;
308  }
309 
310  friend raw_ostream &operator<<(raw_ostream &OS, const Error &E) {
311    if (auto P = E.getPtr())
312      P->log(OS);
313    else
314      OS << "success";
315    return OS;
316  }
317 
318  ErrorInfoBase *Payload = nullptr;
319};
320 
321/// Subclass of Error for the sole purpose of identifying the success path in
322/// the type system. This allows to catch invalid conversion to Expected<T> at
323/// compile time.
324class ErrorSuccess final : public Error {};
325 
326inline ErrorSuccess Error::success() { return ErrorSuccess(); }
327 
328/// Make a Error instance representing failure using the given error info
329/// type.
330template <typename ErrT, typename... ArgTs> Error make_error(ArgTs &&... Args) {
331  return Error(std::make_unique<ErrT>(std::forward<ArgTs>(Args)...));
332}
333 
334/// Base class for user error types. Users should declare their error types
335/// like:
336///
337/// class MyError : public ErrorInfo<MyError> {
338///   ....
339/// };
340///
341/// This class provides an implementation of the ErrorInfoBase::kind
342/// method, which is used by the Error RTTI system.
343template <typename ThisErrT, typename ParentErrT = ErrorInfoBase>
344class ErrorInfo : public ParentErrT {
345public:
346  using ParentErrT::ParentErrT; // inherit constructors
347 
348  static const void *classID() { return &ThisErrT::ID; }
349 
350  const void *dynamicClassID() const override { return &ThisErrT::ID; }
351 
352  bool isA(const void *const ClassID) const override {
353    return ClassID == classID() || ParentErrT::isA(ClassID);
354  }
355};
356 
357/// Special ErrorInfo subclass representing a list of ErrorInfos.
358/// Instances of this class are constructed by joinError.
359class ErrorList final : public ErrorInfo<ErrorList> {
360  // handleErrors needs to be able to iterate the payload list of an
361  // ErrorList.
362  template <typename... HandlerTs>
363  friend Error handleErrors(Error E, HandlerTs &&... Handlers);
364 
365  // joinErrors is implemented in terms of join.
366  friend Error joinErrors(Error, Error);
367 
368public:
369  void log(raw_ostream &OS) const override {
370    OS << "Multiple errors:\n";
371    for (auto &ErrPayload : Payloads) {
372      ErrPayload->log(OS);
373      OS << "\n";
374    }
375  }
376 
377  std::error_code convertToErrorCode() const override;
378 
379  // Used by ErrorInfo::classID.
380  static char ID;
381 
382private:
383  ErrorList(std::unique_ptr<ErrorInfoBase> Payload1,
384            std::unique_ptr<ErrorInfoBase> Payload2) {
385    assert(!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() &&((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 386, __PRETTY_FUNCTION__))
386           "ErrorList constructor payloads should be singleton errors")((!Payload1->isA<ErrorList>() && !Payload2->
isA<ErrorList>() && "ErrorList constructor payloads should be singleton errors"
) ? static_cast<void> (0) : __assert_fail ("!Payload1->isA<ErrorList>() && !Payload2->isA<ErrorList>() && \"ErrorList constructor payloads should be singleton errors\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 386, __PRETTY_FUNCTION__));
387    Payloads.push_back(std::move(Payload1));
388    Payloads.push_back(std::move(Payload2));
389  }
390 
391  static Error join(Error E1, Error E2) {
392    if (!E1)
393      return E2;
394    if (!E2)
395      return E1;
396    if (E1.isA<ErrorList>()) {
397      auto &E1List = static_cast<ErrorList &>(*E1.getPtr());
398      if (E2.isA<ErrorList>()) {
399        auto E2Payload = E2.takePayload();
400        auto &E2List = static_cast<ErrorList &>(*E2Payload);
401        for (auto &Payload : E2List.Payloads)
402          E1List.Payloads.push_back(std::move(Payload));
403      } else
404        E1List.Payloads.push_back(E2.takePayload());
405 
406      return E1;
407    }
408    if (E2.isA<ErrorList>()) {
409      auto &E2List = static_cast<ErrorList &>(*E2.getPtr());
410      E2List.Payloads.insert(E2List.Payloads.begin(), E1.takePayload());
411      return E2;
412    }
413    return Error(std::unique_ptr<ErrorList>(
414        new ErrorList(E1.takePayload(), E2.takePayload())));
415  }
416 
417  std::vector<std::unique_ptr<ErrorInfoBase>> Payloads;
418};
419 
420/// Concatenate errors. The resulting Error is unchecked, and contains the
421/// ErrorInfo(s), if any, contained in E1, followed by the
422/// ErrorInfo(s), if any, contained in E2.
423inline Error joinErrors(Error E1, Error E2) {
424  return ErrorList::join(std::move(E1), std::move(E2));
425}
426 
427/// Tagged union holding either a T or a Error.
428///
429/// This class parallels ErrorOr, but replaces error_code with Error. Since
430/// Error cannot be copied, this class replaces getError() with
431/// takeError(). It also adds an bool errorIsA<ErrT>() method for testing the
432/// error class type.
433template <class T> class LLVM_NODISCARD[[clang::warn_unused_result]] Expected {
434  template <class T1> friend class ExpectedAsOutParameter;
435  template <class OtherT> friend class Expected;
436 
437  static const bool isRef = std::is_reference<T>::value;
438 
439  using wrap = std::reference_wrapper<typename std::remove_reference<T>::type>;
440 
441  using error_type = std::unique_ptr<ErrorInfoBase>;
442 
443public:
444  using storage_type = typename std::conditional<isRef, wrap, T>::type;
445  using value_type = T;
446 
447private:
448  using reference = typename std::remove_reference<T>::type &;
449  using const_reference = const typename std::remove_reference<T>::type &;
450  using pointer = typename std::remove_reference<T>::type *;
451  using const_pointer = const typename std::remove_reference<T>::type *;
452 
453public:
454  /// Create an Expected<T> error value from the given Error.
455  Expected(Error Err)
456      : HasError(true)
457#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
458        // Expected is unchecked upon construction in Debug builds.
459        , Unchecked(true)
460#endif
461  {
462    assert(Err && "Cannot create Expected<T> from Error success value.")((Err && "Cannot create Expected<T> from Error success value."
) ? static_cast<void> (0) : __assert_fail ("Err && \"Cannot create Expected<T> from Error success value.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 462, __PRETTY_FUNCTION__));
463    new (getErrorStorage()) error_type(Err.takePayload());
464  }
465 
466  /// Forbid to convert from Error::success() implicitly, this avoids having
467  /// Expected<T> foo() { return Error::success(); } which compiles otherwise
468  /// but triggers the assertion above.
469  Expected(ErrorSuccess) = delete;
470 
471  /// Create an Expected<T> success value from the given OtherT value, which
472  /// must be convertible to T.
473  template <typename OtherT>
474  Expected(OtherT &&Val,
475           typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
476               * = nullptr)
477      : HasError(false)
478#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
479        // Expected is unchecked upon construction in Debug builds.
480        , Unchecked(true)
481#endif
482  {
483    new (getStorage()) storage_type(std::forward<OtherT>(Val));
484  }
485 
486  /// Move construct an Expected<T> value.
487  Expected(Expected &&Other) { moveConstruct(std::move(Other)); }
488 
489  /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
490  /// must be convertible to T.
491  template <class OtherT>
492  Expected(Expected<OtherT> &&Other,
493           typename std::enable_if<std::is_convertible<OtherT, T>::value>::type
494               * = nullptr) {
495    moveConstruct(std::move(Other));
496  }
497 
498  /// Move construct an Expected<T> value from an Expected<OtherT>, where OtherT
499  /// isn't convertible to T.
500  template <class OtherT>
501  explicit Expected(
502      Expected<OtherT> &&Other,
503      typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * =
504          nullptr) {
505    moveConstruct(std::move(Other));
506  }
507 
508  /// Move-assign from another Expected<T>.
509  Expected &operator=(Expected &&Other) {
510    moveAssign(std::move(Other));
511    return *this;
512  }
513 
514  /// Destroy an Expected<T>.
515  ~Expected() {
516    assertIsChecked();
517    if (!HasError)
518      getStorage()->~storage_type();
519    else
520      getErrorStorage()->~error_type();
521  }
522 
523  /// Return false if there is an error.
524  explicit operator bool() {
525#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
526    Unchecked = HasError;
527#endif
528    return !HasError;
529  }
530 
531  /// Returns a reference to the stored T value.
532  reference get() {
533    assertIsChecked();
534    return *getStorage();
535  }
536 
537  /// Returns a const reference to the stored T value.
538  const_reference get() const {
539    assertIsChecked();
540    return const_cast<Expected<T> *>(this)->get();
541  }
542 
543  /// Check that this Expected<T> is an error of type ErrT.
544  template <typename ErrT> bool errorIsA() const {
545    return HasError && (*getErrorStorage())->template isA<ErrT>();
546  }
547 
548  /// Take ownership of the stored error.
549  /// After calling this the Expected<T> is in an indeterminate state that can
550  /// only be safely destructed. No further calls (beside the destructor) should
551  /// be made on the Expected<T> value.
552  Error takeError() {
553#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
554    Unchecked = false;
555#endif
556    return HasError ? Error(std::move(*getErrorStorage())) : Error::success();
557  }
558 
559  /// Returns a pointer to the stored T value.
560  pointer operator->() {
561    assertIsChecked();
562    return toPointer(getStorage());
563  }
564 
565  /// Returns a const pointer to the stored T value.
566  const_pointer operator->() const {
567    assertIsChecked();
568    return toPointer(getStorage());
569  }
570 
571  /// Returns a reference to the stored T value.
572  reference operator*() {
573    assertIsChecked();
574    return *getStorage();
575  }
576 
577  /// Returns a const reference to the stored T value.
578  const_reference operator*() const {
579    assertIsChecked();
580    return *getStorage();
581  }
582 
583private:
584  template <class T1>
585  static bool compareThisIfSameType(const T1 &a, const T1 &b) {
586    return &a == &b;
587  }
588 
589  template <class T1, class T2>
590  static bool compareThisIfSameType(const T1 &a, const T2 &b) {
591    return false;
592  }
593 
594  template <class OtherT> void moveConstruct(Expected<OtherT> &&Other) {
595    HasError = Other.HasError;
596#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
597    Unchecked = true;
598    Other.Unchecked = false;
599#endif
600 
601    if (!HasError)
602      new (getStorage()) storage_type(std::move(*Other.getStorage()));
603    else
604      new (getErrorStorage()) error_type(std::move(*Other.getErrorStorage()));
605  }
606 
607  template <class OtherT> void moveAssign(Expected<OtherT> &&Other) {
608    assertIsChecked();
609 
610    if (compareThisIfSameType(*this, Other))
611      return;
612 
613    this->~Expected();
614    new (this) Expected(std::move(Other));
615  }
616 
617  pointer toPointer(pointer Val) { return Val; }
618 
619  const_pointer toPointer(const_pointer Val) const { return Val; }
620 
621  pointer toPointer(wrap *Val) { return &Val->get(); }
622 
623  const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
624 
625  storage_type *getStorage() {
626    assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 626, __PRETTY_FUNCTION__));
627    return reinterpret_cast<storage_type *>(TStorage.buffer);
628  }
629 
630  const storage_type *getStorage() const {
631    assert(!HasError && "Cannot get value when an error exists!")((!HasError && "Cannot get value when an error exists!"
) ? static_cast<void> (0) : __assert_fail ("!HasError && \"Cannot get value when an error exists!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 631, __PRETTY_FUNCTION__));
632    return reinterpret_cast<const storage_type *>(TStorage.buffer);
633  }
634 
635  error_type *getErrorStorage() {
636    assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 636, __PRETTY_FUNCTION__));
637    return reinterpret_cast<error_type *>(ErrorStorage.buffer);
638  }
639 
640  const error_type *getErrorStorage() const {
641    assert(HasError && "Cannot get error when a value exists!")((HasError && "Cannot get error when a value exists!"
) ? static_cast<void> (0) : __assert_fail ("HasError && \"Cannot get error when a value exists!\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 641, __PRETTY_FUNCTION__));
642    return reinterpret_cast<const error_type *>(ErrorStorage.buffer);
643  }
644 
645  // Used by ExpectedAsOutParameter to reset the checked flag.
646  void setUnchecked() {
647#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
648    Unchecked = true;
649#endif
650  }
651 
652#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
653  LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn))
654  LLVM_ATTRIBUTE_NOINLINE__attribute__((noinline))
655  void fatalUncheckedExpected() const {
656    dbgs() << "Expected<T> must be checked before access or destruction.\n";
657    if (HasError) {
658      dbgs() << "Unchecked Expected<T> contained error:\n";
659      (*getErrorStorage())->log(dbgs());
660    } else
661      dbgs() << "Expected<T> value was in success state. (Note: Expected<T> "
662                "values in success mode must still be checked prior to being "
663                "destroyed).\n";
664    abort();
665  }
666#endif
667 
668  void assertIsChecked() {
669#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
670    if (LLVM_UNLIKELY(Unchecked)__builtin_expect((bool)(Unchecked), false))
671      fatalUncheckedExpected();
672#endif
673  }
674 
675  union {
676    AlignedCharArrayUnion<storage_type> TStorage;
677    AlignedCharArrayUnion<error_type> ErrorStorage;
678  };
679  bool HasError : 1;
680#if LLVM_ENABLE_ABI_BREAKING_CHECKS1
681  bool Unchecked : 1;
682#endif
683};
684 
685/// Report a serious error, calling any installed error handler. See
686/// ErrorHandling.h.
687LLVM_ATTRIBUTE_NORETURN__attribute__((noreturn)) void report_fatal_error(Error Err,
688                                                bool gen_crash_diag = true);
689 
690/// Report a fatal error if Err is a failure value.
691///
692/// This function can be used to wrap calls to fallible functions ONLY when it
693/// is known that the Error will always be a success value. E.g.
694///
695///   @code{.cpp}
696///   // foo only attempts the fallible operation if DoFallibleOperation is
697///   // true. If DoFallibleOperation is false then foo always returns
698///   // Error::success().
699///   Error foo(bool DoFallibleOperation);
700///
701///   cantFail(foo(false));
702///   @endcode
703inline void cantFail(Error Err, const char *Msg = nullptr) {
704  if (Err) {
705    if (!Msg)
706      Msg = "Failure value returned from cantFail wrapped call";
707    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 707);
708  }
709}
710 
711/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
712/// returns the contained value.
713///
714/// This function can be used to wrap calls to fallible functions ONLY when it
715/// is known that the Error will always be a success value. E.g.
716///
717///   @code{.cpp}
718///   // foo only attempts the fallible operation if DoFallibleOperation is
719///   // true. If DoFallibleOperation is false then foo always returns an int.
720///   Expected<int> foo(bool DoFallibleOperation);
721///
722///   int X = cantFail(foo(false));
723///   @endcode
724template <typename T>
725T cantFail(Expected<T> ValOrErr, const char *Msg = nullptr) {
726  if (ValOrErr)
727    return std::move(*ValOrErr);
728  else {
729    if (!Msg)
730      Msg = "Failure value returned from cantFail wrapped call";
731    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 731);
732  }
733}
734 
735/// Report a fatal error if ValOrErr is a failure value, otherwise unwraps and
736/// returns the contained reference.
737///
738/// This function can be used to wrap calls to fallible functions ONLY when it
739/// is known that the Error will always be a success value. E.g.
740///
741///   @code{.cpp}
742///   // foo only attempts the fallible operation if DoFallibleOperation is
743///   // true. If DoFallibleOperation is false then foo always returns a Bar&.
744///   Expected<Bar&> foo(bool DoFallibleOperation);
745///
746///   Bar &X = cantFail(foo(false));
747///   @endcode
748template <typename T>
749T& cantFail(Expected<T&> ValOrErr, const char *Msg = nullptr) {
750  if (ValOrErr)
751    return *ValOrErr;
752  else {
753    if (!Msg)
754      Msg = "Failure value returned from cantFail wrapped call";
755    llvm_unreachable(Msg)::llvm::llvm_unreachable_internal(Msg, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 755);
756  }
757}
758 
759/// Helper for testing applicability of, and applying, handlers for
760/// ErrorInfo types.
761template <typename HandlerT>
762class ErrorHandlerTraits
763    : public ErrorHandlerTraits<decltype(
764          &std::remove_reference<HandlerT>::type::operator())> {};
765 
766// Specialization functions of the form 'Error (const ErrT&)'.
767template <typename ErrT> class ErrorHandlerTraits<Error (&)(ErrT &)> {
768public:
769  static bool appliesTo(const ErrorInfoBase &E) {
770    return E.template isA<ErrT>();
771  }
772 
773  template <typename HandlerT>
774  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
775    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 775, __PRETTY_FUNCTION__));
776    return H(static_cast<ErrT &>(*E));
777  }
778};
779 
780// Specialization functions of the form 'void (const ErrT&)'.
781template <typename ErrT> class ErrorHandlerTraits<void (&)(ErrT &)> {
782public:
783  static bool appliesTo(const ErrorInfoBase &E) {
784    return E.template isA<ErrT>();
785  }
786 
787  template <typename HandlerT>
788  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
789    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 789, __PRETTY_FUNCTION__));
790    H(static_cast<ErrT &>(*E));
791    return Error::success();
792  }
793};
794 
795/// Specialization for functions of the form 'Error (std::unique_ptr<ErrT>)'.
796template <typename ErrT>
797class ErrorHandlerTraits<Error (&)(std::unique_ptr<ErrT>)> {
798public:
799  static bool appliesTo(const ErrorInfoBase &E) {
800    return E.template isA<ErrT>();
801  }
802 
803  template <typename HandlerT>
804  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
805    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 805, __PRETTY_FUNCTION__));
806    std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
807    return H(std::move(SubE));
808  }
809};
810 
811/// Specialization for functions of the form 'void (std::unique_ptr<ErrT>)'.
812template <typename ErrT>
813class ErrorHandlerTraits<void (&)(std::unique_ptr<ErrT>)> {
814public:
815  static bool appliesTo(const ErrorInfoBase &E) {
816    return E.template isA<ErrT>();
817  }
818 
819  template <typename HandlerT>
820  static Error apply(HandlerT &&H, std::unique_ptr<ErrorInfoBase> E) {
821    assert(appliesTo(*E) && "Applying incorrect handler")((appliesTo(*E) && "Applying incorrect handler") ? static_cast
<void> (0) : __assert_fail ("appliesTo(*E) && \"Applying incorrect handler\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 821, __PRETTY_FUNCTION__));
822    std::unique_ptr<ErrT> SubE(static_cast<ErrT *>(E.release()));
823    H(std::move(SubE));
824    return Error::success();
825  }
826};
827 
828// Specialization for member functions of the form 'RetT (const ErrT&)'.
829template <typename C, typename RetT, typename ErrT>
830class ErrorHandlerTraits<RetT (C::*)(ErrT &)>
831    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
832 
833// Specialization for member functions of the form 'RetT (const ErrT&) const'.
834template <typename C, typename RetT, typename ErrT>
835class ErrorHandlerTraits<RetT (C::*)(ErrT &) const>
836    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
837 
838// Specialization for member functions of the form 'RetT (const ErrT&)'.
839template <typename C, typename RetT, typename ErrT>
840class ErrorHandlerTraits<RetT (C::*)(const ErrT &)>
841    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
842 
843// Specialization for member functions of the form 'RetT (const ErrT&) const'.
844template <typename C, typename RetT, typename ErrT>
845class ErrorHandlerTraits<RetT (C::*)(const ErrT &) const>
846    : public ErrorHandlerTraits<RetT (&)(ErrT &)> {};
847 
848/// Specialization for member functions of the form
849/// 'RetT (std::unique_ptr<ErrT>)'.
850template <typename C, typename RetT, typename ErrT>
851class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>)>
852    : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
853 
854/// Specialization for member functions of the form
855/// 'RetT (std::unique_ptr<ErrT>) const'.
856template <typename C, typename RetT, typename ErrT>
857class ErrorHandlerTraits<RetT (C::*)(std::unique_ptr<ErrT>) const>
858    : public ErrorHandlerTraits<RetT (&)(std::unique_ptr<ErrT>)> {};
859 
860inline Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload) {
861  return Error(std::move(Payload));
862}
863 
864template <typename HandlerT, typename... HandlerTs>
865Error handleErrorImpl(std::unique_ptr<ErrorInfoBase> Payload,
866                      HandlerT &&Handler, HandlerTs &&... Handlers) {
867  if (ErrorHandlerTraits<HandlerT>::appliesTo(*Payload))
868    return ErrorHandlerTraits<HandlerT>::apply(std::forward<HandlerT>(Handler),
869                                               std::move(Payload));
870  return handleErrorImpl(std::move(Payload),
871                         std::forward<HandlerTs>(Handlers)...);
872}
873 
874/// Pass the ErrorInfo(s) contained in E to their respective handlers. Any
875/// unhandled errors (or Errors returned by handlers) are re-concatenated and
876/// returned.
877/// Because this function returns an error, its result must also be checked
878/// or returned. If you intend to handle all errors use handleAllErrors
879/// (which returns void, and will abort() on unhandled errors) instead.
880template <typename... HandlerTs>
881Error handleErrors(Error E, HandlerTs &&... Hs) {
882  if (!E)
883    return Error::success();
884 
885  std::unique_ptr<ErrorInfoBase> Payload = E.takePayload();
886 
887  if (Payload->isA<ErrorList>()) {
888    ErrorList &List = static_cast<ErrorList &>(*Payload);
889    Error R;
890    for (auto &P : List.Payloads)
891      R = ErrorList::join(
892          std::move(R),
893          handleErrorImpl(std::move(P), std::forward<HandlerTs>(Hs)...));
894    return R;
895  }
896 
897  return handleErrorImpl(std::move(Payload), std::forward<HandlerTs>(Hs)...);
898}
899 
900/// Behaves the same as handleErrors, except that by contract all errors
901/// *must* be handled by the given handlers (i.e. there must be no remaining
902/// errors after running the handlers, or llvm_unreachable is called).
903template <typename... HandlerTs>
904void handleAllErrors(Error E, HandlerTs &&... Handlers) {
905  cantFail(handleErrors(std::move(E), std::forward<HandlerTs>(Handlers)...));
906}
907 
908/// Check that E is a non-error, then drop it.
909/// If E is an error, llvm_unreachable will be called.
910inline void handleAllErrors(Error E) {
911  cantFail(std::move(E));
912}
913 
914/// Handle any errors (if present) in an Expected<T>, then try a recovery path.
915///
916/// If the incoming value is a success value it is returned unmodified. If it
917/// is a failure value then it the contained error is passed to handleErrors.
918/// If handleErrors is able to handle the error then the RecoveryPath functor
919/// is called to supply the final result. If handleErrors is not able to
920/// handle all errors then the unhandled errors are returned.
921///
922/// This utility enables the follow pattern:
923///
924///   @code{.cpp}
925///   enum FooStrategy { Aggressive, Conservative };
926///   Expected<Foo> foo(FooStrategy S);
927///
928///   auto ResultOrErr =
929///     handleExpected(
930///       foo(Aggressive),
931///       []() { return foo(Conservative); },
932///       [](AggressiveStrategyError&) {
933///         // Implicitly conusme this - we'll recover by using a conservative
934///         // strategy.
935///       });
936///
937///   @endcode
938template <typename T, typename RecoveryFtor, typename... HandlerTs>
939Expected<T> handleExpected(Expected<T> ValOrErr, RecoveryFtor &&RecoveryPath,
940                           HandlerTs &&... Handlers) {
941  if (ValOrErr)
942    return ValOrErr;
943 
944  if (auto Err = handleErrors(ValOrErr.takeError(),
945                              std::forward<HandlerTs>(Handlers)...))
946    return std::move(Err);
947 
948  return RecoveryPath();
949}
950 
951/// Log all errors (if any) in E to OS. If there are any errors, ErrorBanner
952/// will be printed before the first one is logged. A newline will be printed
953/// after each error.
954///
955/// This function is compatible with the helpers from Support/WithColor.h. You
956/// can pass any of them as the OS. Please consider using them instead of
957/// including 'error: ' in the ErrorBanner.
958///
959/// This is useful in the base level of your program to allow clean termination
960/// (allowing clean deallocation of resources, etc.), while reporting error
961/// information to the user.
962void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner = {});
963 
964/// Write all error messages (if any) in E to a string. The newline character
965/// is used to separate error messages.
966inline std::string toString(Error E) {
967  SmallVector<std::string, 2> Errors;
968  handleAllErrors(std::move(E), [&Errors](const ErrorInfoBase &EI) {
969    Errors.push_back(EI.message());
970  });
971  return join(Errors.begin(), Errors.end(), "\n");
972}
973 
974/// Consume a Error without doing anything. This method should be used
975/// only where an error can be considered a reasonable and expected return
976/// value.
977///
978/// Uses of this method are potentially indicative of design problems: If it's
979/// legitimate to do nothing while processing an "error", the error-producer
980/// might be more clearly refactored to return an Optional<T>.
981inline void consumeError(Error Err) {
982  handleAllErrors(std::move(Err), [](const ErrorInfoBase &) {});
983}
984 
985/// Convert an Expected to an Optional without doing anything. This method
986/// should be used only where an error can be considered a reasonable and
987/// expected return value.
988///
989/// Uses of this method are potentially indicative of problems: perhaps the
990/// error should be propagated further, or the error-producer should just
991/// return an Optional in the first place.
992template <typename T> Optional<T> expectedToOptional(Expected<T> &&E) {
993  if (E)
994    return std::move(*E);
995  consumeError(E.takeError());
996  return None;
997}
998 
999/// Helper for converting an Error to a bool.
1000///
1001/// This method returns true if Err is in an error state, or false if it is
1002/// in a success state.  Puts Err in a checked state in both cases (unlike
1003/// Error::operator bool(), which only does this for success states).
1004inline bool errorToBool(Error Err) {
1005  bool IsError = static_cast<bool>(Err);
1006  if (IsError)
1007    consumeError(std::move(Err));
1008  return IsError;
1009}
1010 
1011/// Helper for Errors used as out-parameters.
1012///
1013/// This helper is for use with the Error-as-out-parameter idiom, where an error
1014/// is passed to a function or method by reference, rather than being returned.
1015/// In such cases it is helpful to set the checked bit on entry to the function
1016/// so that the error can be written to (unchecked Errors abort on assignment)
1017/// and clear the checked bit on exit so that clients cannot accidentally forget
1018/// to check the result. This helper performs these actions automatically using
1019/// RAII:
1020///
1021///   @code{.cpp}
1022///   Result foo(Error &Err) {
1023///     ErrorAsOutParameter ErrAsOutParam(&Err); // 'Checked' flag set
1024///     // <body of foo>
1025///     // <- 'Checked' flag auto-cleared when ErrAsOutParam is destructed.
1026///   }
1027///   @endcode
1028///
1029/// ErrorAsOutParameter takes an Error* rather than Error& so that it can be
1030/// used with optional Errors (Error pointers that are allowed to be null). If
1031/// ErrorAsOutParameter took an Error reference, an instance would have to be
1032/// created inside every condition that verified that Error was non-null. By
1033/// taking an Error pointer we can just create one instance at the top of the
1034/// function.
1035class ErrorAsOutParameter {
1036public:
1037  ErrorAsOutParameter(Error *Err) : Err(Err) {
1038    // Raise the checked bit if Err is success.
1039    if (Err)
1040      (void)!!*Err;
1041  }
1042 
1043  ~ErrorAsOutParameter() {
1044    // Clear the checked bit.
1045    if (Err && !*Err)
1046      *Err = Error::success();
1047  }
1048 
1049private:
1050  Error *Err;
1051};
1052 
1053/// Helper for Expected<T>s used as out-parameters.
1054///
1055/// See ErrorAsOutParameter.
1056template <typename T>
1057class ExpectedAsOutParameter {
1058public:
1059  ExpectedAsOutParameter(Expected<T> *ValOrErr)
1060    : ValOrErr(ValOrErr) {
1061    if (ValOrErr)
1062      (void)!!*ValOrErr;
1063  }
1064 
1065  ~ExpectedAsOutParameter() {
1066    if (ValOrErr)
1067      ValOrErr->setUnchecked();
1068  }
1069 
1070private:
1071  Expected<T> *ValOrErr;
1072};
1073 
1074/// This class wraps a std::error_code in a Error.
1075///
1076/// This is useful if you're writing an interface that returns a Error
1077/// (or Expected) and you want to call code that still returns
1078/// std::error_codes.
1079class ECError : public ErrorInfo<ECError> {
1080  friend Error errorCodeToError(std::error_code);
1081 
1082  virtual void anchor() override;
1083 
1084public:
1085  void setErrorCode(std::error_code EC) { this->EC = EC; }
1086  std::error_code convertToErrorCode() const override { return EC; }
1087  void log(raw_ostream &OS) const override { OS << EC.message(); }
1088 
1089  // Used by ErrorInfo::classID.
1090  static char ID;
1091 
1092protected:
1093  ECError() = default;
1094  ECError(std::error_code EC) : EC(EC) {}
1095 
1096  std::error_code EC;
1097};
1098 
1099/// The value returned by this function can be returned from convertToErrorCode
1100/// for Error values where no sensible translation to std::error_code exists.
1101/// It should only be used in this situation, and should never be used where a
1102/// sensible conversion to std::error_code is available, as attempts to convert
1103/// to/from this error will result in a fatal error. (i.e. it is a programmatic
1104///error to try to convert such a value).
1105std::error_code inconvertibleErrorCode();
1106 
1107/// Helper for converting an std::error_code to a Error.
1108Error errorCodeToError(std::error_code EC);
1109 
1110/// Helper for converting an ECError to a std::error_code.
1111///
1112/// This method requires that Err be Error() or an ECError, otherwise it
1113/// will trigger a call to abort().
1114std::error_code errorToErrorCode(Error Err);
1115 
1116/// Convert an ErrorOr<T> to an Expected<T>.
1117template <typename T> Expected<T> errorOrToExpected(ErrorOr<T> &&EO) {
1118  if (auto EC = EO.getError())
1119    return errorCodeToError(EC);
1120  return std::move(*EO);
1121}
1122 
1123/// Convert an Expected<T> to an ErrorOr<T>.
1124template <typename T> ErrorOr<T> expectedToErrorOr(Expected<T> &&E) {
1125  if (auto Err = E.takeError())
1126    return errorToErrorCode(std::move(Err));
1127  return std::move(*E);
1128}
1129 
1130/// This class wraps a string in an Error.
1131///
1132/// StringError is useful in cases where the client is not expected to be able
1133/// to consume the specific error message programmatically (for example, if the
1134/// error message is to be presented to the user).
1135///
1136/// StringError can also be used when additional information is to be printed
1137/// along with a error_code message. Depending on the constructor called, this
1138/// class can either display:
1139///    1. the error_code message (ECError behavior)
1140///    2. a string
1141///    3. the error_code message and a string
1142///
1143/// These behaviors are useful when subtyping is required; for example, when a
1144/// specific library needs an explicit error type. In the example below,
1145/// PDBError is derived from StringError:
1146///
1147///   @code{.cpp}
1148///   Expected<int> foo() {
1149///      return llvm::make_error<PDBError>(pdb_error_code::dia_failed_loading,
1150///                                        "Additional information");
1151///   }
1152///   @endcode
1153///
1154class StringError : public ErrorInfo<StringError> {
1155public:
1156  static char ID;
1157 
1158  // Prints EC + S and converts to EC
1159  StringError(std::error_code EC, const Twine &S = Twine());
1160 
1161  // Prints S and converts to EC
1162  StringError(const Twine &S, std::error_code EC);
1163 
1164  void log(raw_ostream &OS) const override;
1165  std::error_code convertToErrorCode() const override;
1166 
1167  const std::string &getMessage() const { return Msg; }
1168 
1169private:
1170  std::string Msg;
1171  std::error_code EC;
1172  const bool PrintMsgOnly = false;
1173};
1174 
1175/// Create formatted StringError object.
1176template <typename... Ts>
1177inline Error createStringError(std::error_code EC, char const *Fmt,
1178                               const Ts &... Vals) {
1179  std::string Buffer;
1180  raw_string_ostream Stream(Buffer);
1181  Stream << format(Fmt, Vals...);
1182  return make_error<StringError>(Stream.str(), EC);
1183}
1184 
1185Error createStringError(std::error_code EC, char const *Msg);
1186 
1187inline Error createStringError(std::error_code EC, const Twine &S) {
1188  return createStringError(EC, S.str().c_str());
1189}
1190 
1191template <typename... Ts>
1192inline Error createStringError(std::errc EC, char const *Fmt,
1193                               const Ts &... Vals) {
1194  return createStringError(std::make_error_code(EC), Fmt, Vals...);
1195}
1196 
1197/// This class wraps a filename and another Error.
1198///
1199/// In some cases, an error needs to live along a 'source' name, in order to
1200/// show more detailed information to the user.
1201class FileError final : public ErrorInfo<FileError> {
1202 
1203  friend Error createFileError(const Twine &, Error);
1204  friend Error createFileError(const Twine &, size_t, Error);
1205 
1206public:
1207  void log(raw_ostream &OS) const override {
1208    assert(Err && !FileName.empty() && "Trying to log after takeError().")((Err && !FileName.empty() && "Trying to log after takeError()."
) ? static_cast<void> (0) : __assert_fail ("Err && !FileName.empty() && \"Trying to log after takeError().\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 1208, __PRETTY_FUNCTION__));
1209    OS << "'" << FileName << "': ";
1210    if (Line.hasValue())
1211      OS << "line " << Line.getValue() << ": ";
1212    Err->log(OS);
1213  }
1214 
1215  Error takeError() { return Error(std::move(Err)); }
1216 
1217  std::error_code convertToErrorCode() const override;
1218 
1219  // Used by ErrorInfo::classID.
1220  static char ID;
1221 
1222private:
1223  FileError(const Twine &F, Optional<size_t> LineNum,
1224            std::unique_ptr<ErrorInfoBase> E) {
1225    assert(E && "Cannot create FileError from Error success value.")((E && "Cannot create FileError from Error success value."
) ? static_cast<void> (0) : __assert_fail ("E && \"Cannot create FileError from Error success value.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 1225, __PRETTY_FUNCTION__));
1226    assert(!F.isTriviallyEmpty() &&((!F.isTriviallyEmpty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.isTriviallyEmpty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 1227, __PRETTY_FUNCTION__))
1227           "The file name provided to FileError must not be empty.")((!F.isTriviallyEmpty() && "The file name provided to FileError must not be empty."
) ? static_cast<void> (0) : __assert_fail ("!F.isTriviallyEmpty() && \"The file name provided to FileError must not be empty.\""
, "/build/llvm-toolchain-snapshot-10~svn374877/include/llvm/Support/Error.h"
, 1227, __PRETTY_FUNCTION__));
1228    FileName = F.str();
1229    Err = std::move(E);
1230    Line = std::move(LineNum);
1231  }
1232 
1233  static Error build(const Twine &F, Optional<size_t> Line, Error E) {
1234    return Error(
1235        std::unique_ptr<FileError>(new FileError(F, Line, E.takePayload())));
1236  }
1237 
1238  std::string FileName;
1239  Optional<size_t> Line;
1240  std::unique_ptr<ErrorInfoBase> Err;
1241};
1242 
1243/// Concatenate a source file path and/or name with an Error. The resulting
1244/// Error is unchecked.
1245inline Error createFileError(const Twine &F, Error E) {
1246  return FileError::build(F, Optional<size_t>(), std::move(E));
1247}
1248 
1249/// Concatenate a source file path and/or name with line number and an Error.
1250/// The resulting Error is unchecked.
1251inline Error createFileError(const Twine &F, size_t Line, Error E) {
1252  return FileError::build(F, Optional<size_t>(Line), std::move(E));
1253}
1254 
1255/// Concatenate a source file path and/or name with a std::error_code 
1256/// to form an Error object.
1257inline Error createFileError(const Twine &F, std::error_code EC) {
1258  return createFileError(F, errorCodeToError(EC));
1259}
1260 
1261/// Concatenate a source file path and/or name with line number and
1262/// std::error_code to form an Error object.
1263inline Error createFileError(const Twine &F, size_t Line, std::error_code EC) {
1264  return createFileError(F, Line, errorCodeToError(EC));
1265}
1266 
1267Error createFileError(const Twine &F, ErrorSuccess) = delete;
1268 
1269/// Helper for check-and-exit error handling.
1270///
1271/// For tool use only. NOT FOR USE IN LIBRARY CODE.
1272///
1273class ExitOnError {
1274public:
1275  /// Create an error on exit helper.
1276  ExitOnError(std::string Banner = "", int DefaultErrorExitCode = 1)
1277      : Banner(std::move(Banner)),
1278        GetExitCode([=](const Error &) { return DefaultErrorExitCode; }) {}
1279 
1280  /// Set the banner string for any errors caught by operator().
1281  void setBanner(std::string Banner) { this->Banner = std::move(Banner); }
1282 
1283  /// Set the exit-code mapper function.
1284  void setExitCodeMapper(std::function<int(const Error &)> GetExitCode) {
1285    this->GetExitCode = std::move(GetExitCode);
1286  }
1287 
1288  /// Check Err. If it's in a failure state log the error(s) and exit.
1289  void operator()(Error Err) const { checkError(std::move(Err)); }
1290 
1291  /// Check E. If it's in a success state then return the contained value. If
1292  /// it's in a failure state log the error(s) and exit.
1293  template <typename T> T operator()(Expected<T> &&E) const {
1294    checkError(E.takeError());
1295    return std::move(*E);
1296  }
1297 
1298  /// Check E. If it's in a success state then return the contained reference. If
1299  /// it's in a failure state log the error(s) and exit.
1300  template <typename T> T& operator()(Expected<T&> &&E) const {
1301    checkError(E.takeError());
1302    return *E;
1303  }
1304 
1305private:
1306  void checkError(Error Err) const {
1307    if (Err) {
1308      int ExitCode = GetExitCode(Err);
1309      logAllUnhandledErrors(std::move(Err), errs(), Banner);
1310      exit(ExitCode);
1311    }
1312  }
1313 
1314  std::string Banner;
1315  std::function<int(const Error &)> GetExitCode;
1316};
1317 
1318/// Conversion from Error to LLVMErrorRef for C error bindings.
1319inline LLVMErrorRef wrap(Error Err) {
1320  return reinterpret_cast<LLVMErrorRef>(Err.takePayload().release());
1321}
1322 
1323/// Conversion from LLVMErrorRef to Error for C error bindings.
1324inline Error unwrap(LLVMErrorRef ErrRef) {
1325  return Error(std::unique_ptr<ErrorInfoBase>(
1326      reinterpret_cast<ErrorInfoBase *>(ErrRef)));
1327}
1328 
1329} // end namespace llvm
1330 
1331#endif // LLVM_SUPPORT_ERROR_H